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Scientific Data Documentation
Epidemiologic Followup Study, 1982-84 Health Care Facility StayDSN: CC37.HANES1FU.FCLY824 NHANES EPIDEMIOLOGIC FOLLOWUP STUDY HEALTH CARE FACILITY STAY 1982-84 Abstract 1982-84 Sandra T. Rothwell Enclosure Date: September 10, 1990 From: NHEFS Statistical Staff Division of Analysis, NCHS Subject: 1982-84 NHANES I Epidemiologic Followup Study Revised Health Care Facility Stay Public Use Data Tape To: Project Officers and Investigators See Addressees Below The revision of the 1982-84 Health Care Facility Stay (HCFS) file has been completed. The original file, the 1982-84 Health Care Facility Record file, only contained information from the medical records obtained from health care facilities. The 1986, the 1987 and the revised 1982-84 Health Care Facility Stay data files include both descriptive information reported by the respondent and the medical information returned from the health care facility. This new format, then, includes information about all possible stays in health care facilities whether or not an actual health care facility record was obtained. At the time the 1986 and 1987 Health Care Facility Stay files were constructed, a comparable 1982-84 file did not exist. However, it was possible to construct a comparable file for 1982-84 because the respondent's descriptive information needed to replicate the content of the 1986 and 1987 files was available in the 1982-84 interview. This information was linked with the medical information on the original file to create the revised file. In addition, during data collection for the 1986 and 1987 files, more medical records for the 1982-84 followup period were obtained. These have been included in the revised file. The resulting data set is more complete than the original and can be used in conjunction with the Health Care Facility Stay files for later followup periods. This Revised 1982-84 Health Care Facility Stay Data File has been finalized and is being released to all collaborators. It replaces the 1982-84 Health Care Facility Record Data file released in 1987. A memo has been sent to your contact person which describes the tape characteristics for this file. Please contact that person for information about accessing your tape. Use of NHEFS Data With the goal of mutual benefit, NCHS requests the cooperation of recipients of data tapes in certain actions related to their use: A. Any published material derived from the data should acknowledge the National Center for Health Statistics (NCHS) as the original source. It should also include a disclaimer which credits any analyses, interpretations, or conclusions reached to the author (recipient of the tape) and not to NCHS, which is responsible only for the initial data. B. Consumers who wish to publish a technical description of the data will make a reasonable effort to insure that the description is not inconsistent with that published by NCHS. This does not mean, however, that NCHS will review such descriptions. C. Authors should provide NCHS with a reprint of published articles which utilize the 1982-84 NHEFS data. Please send reprints to: NHEFS Data Management Staff Division of Analysis National Center for Health Statistics Presidential Building, Room 1080 6525 Belcrest Road Hyattsville, MD 20782 Errors in the Data Tapes The NHEFS Public Use data tapes have been subjected to a great deal of careful editing. However, due to the large volume of data in the series, it is likely that a small number of errors or discrepancies remain undetected. Some continuous data items have extremely high or low values and we have verified that the values have not been incorrectly keyed. In general, the NHEFS data management team has not attempted to resolve substantive data discrepancies that may exist 1) within the 1982-84 NHEFS data tapes, or 2) between the 1982-84 NHEFS data tapes and the data tapes of the original National Health and Nutrition Examination Survey (NHANES I) and other NHEFS followup waves. BACKGROUND Background 1982-84 The first National Health and Nutrition Examination Survey (NHANES I) collected data from a national probability sample of the civilian noninstitutionalized population. The survey, which included a standardized medical examination and questionnaires that covered various topics, took place from 1971 through 1974 and was augmented by an additional national sample in 1974-75. The NHANES I sample included 20,729 persons 25 to 74 years of age, 14,407 (70 percent) of whom underwent the medical examination. Although NHANES I provides a wealth of information on the prevalence of health conditions and risk factors, the cross-sectional nature of the original survey limits its usefulness in studying the effects of clinical, environmental, and behavioral factors and in tracing the natural history of disease. Therefore, the NHANES I Epidemiologic Followup Study (NHEFS) was designed to investigate the association between factors measured at the base- line with the development of specific health conditions. The followup study originated as a joint project between the National Center for Health Statistics (NCHS) and the National Institute on Aging (NIA). The 1982-84 initial followup of the cohort was funded primarily by NIA, with additional financial support from the following components of the National Institutes of Health (NIH) and Public Health Service agencies: National Cancer Institute; National Institute of Mental Health; National Institute on Alcohol Abuse and Alcoholism; National Heart, Lung, and Blood Institute; National Institute of Neurologic and Communicative Disorders and Stroke; National Institute of Arthritis, Diabetes, Digestive, and Kidney Diseases; National Institute of Allergy and Infectious Diseases; and the National Institute of Child Health and Human Development. All of these agencies were involved in both developing topics of import in their specialty areas and designing procedures to collect data that would address these issues. The size and scope of the population in the NHEFS provides a unique opportunity to examine causal relationships in a large, heterogeneous, nationally representative population. The followup study population included the 14,407 participants who were 25 to 74 years of age when they were examined in NHANES I (1971-75). Tracing of subjects began in 1981. Data collection for the followup was conducted from 1982 to 1984, with all data collection completed in August 1984. Copies of all pertinent study materials (tracing materials, questionnaires, authorization forms, and health facility data collection forms) can be found in Appendix VI of the Plan and Operation of the NHANES I Epidemiologic Followup Study 1982-84. (Vital and Health Statistics), Series 1, No. 22. The design of NHEFS consisted of five steps: tracing the subjects or their proxies to a current address; acquiring death certificates; performing in-depth interviews with the subjects or with their proxies; taking pulse, blood pressure, and weight measurements of surviving subjects; obtaining hospital and nursing home records, including pathology reports and electrocardiograms. The first phase of the project was to trace and locate all subjects in the cohort and to determine their vital status. All persons who could not be traced were considered lost to followup. The fact of death had to be confirmed by a death certificate or a proxy interview. In some cases, information about the death of a subject was obtained from neighbors or other tracing contacts. Although this information was noted in the record, these persons were considered lost to followup unless the information was verified by a proxy interview or a death certificate. For subjects who had died, date and place of death were obtained through the tracing process. This information was used to obtain a copy of the death certificate from the appropriate State Vital Statistics office. The tracing process was also used to obtain the current address of surviving subjects as well as to identify a knowledgeable proxy respondent for deceased subjects. Respondents who were identified and located through the tracing procedure were then contacted and asked to participate in a personal interview. In a few cases, respondents who had been traced successfully could not be relocated for the interview. Only vital status as of tracing was available for those subjects. Attempts were made to interview all subjects identified during tracing. Interviews were conducted wherever the respondent resided, including in nursing homes, prisons, mental health facilities, or occasionally at some other convenient location (for example, a parent's home). For surviving subjects, attempts were made to measure the subject's pulse rate, blood pressure (three consecutive readings), and weight. After the physical measurements were completed, the subjects were given written reports of the measurements. The interview was designed to gather information on selected aspects of the subject's health history since the time of the NHANES I exam. This information included a history of the occurrence or recurrence of selected medical conditions, an assessment of behavioral, social, nutritional, and medical risk factors believed to be associated with these conditions, and an assessment of various aspects of functional status. Whenever possible, the questionnaire was designed to retain item comparability between NHANES I and NHEFS in order to measure change over time. However, questionnaire items were modified, added, or deleted when necessary to take advantage of current improvements in questionnaire methodology. Parts D, E, and G of the questionnaire contain items to determine whether or not the subject had an overnight stay in a health care facility after 1970. If a stay was reported, information on the name and address of the facility, the date of the stay, and the reason for the stay was recorded on a special Hospital and Health Care Facility (HHCF) chart on the back cover of the self- administration booklet. The hospitals and nursing homes in which study subjects had reported stays were later contacted and asked to review the subject's medical records for all stays occurring between January 1 of the year of the NHANES I exam up to the date of the 1982-84 interview and to return information abstracted from their records. Limited data were requested on the hospital and nursing home abstract forms. The major items requested were the dates of admission and discharge, the discharge diagnoses and any procedures that may have been performed. For nursing homes the admission diagnoses were reported. In addition to completing abstract forms, facilities were requested to submit photocopies of the "face sheet," and "discharge summary," the third day EKG for myocardial infarction diagnoses, (410 in the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) and of pathology reports for any admission where a new malignancy was diagnosed. Respondents who reported facility stays were asked to sign a Medical Authorization Form that would be used to request the release of hospital record information. These authorization forms were retained on file and a photocopy was sent to each hospital that the respon- dent had identified during the interview. This data collection was conducted between April 1983 and August 1984. The resulting facility abstract records were released in 1987 as the Health Care Facility Record file. As of August 1984, 13,383 (93 percent) of the 14,407 members of the 1982-84 NHEFS cohort had been successfully traced. Interviews were conducted for 12,220 subjects (91 percent of those successfully traced). In addition, 17,127 facility stay records were collected for 6,477 subjects using information obtained from the interview, death certificate, or some other source. Death certificates were obtained for 1,935 (96 percent) of the 2,022 subjects who were known to have died since the NHANES I examination. The data collected from the 1982-84 NHEFS are stored on four separate tapes, the first three of which have been available since 1987. 1) Vital and Tracing Status tape -- contains summary information about the status of the cohort. 2) Interview tape -- contains the data collected from the 1982-84 NHEFS subject and proxy interviews. 3) Mortality Data tape -- contains data abstracted from the death certificates for 1982-84 decedents. 4) Revised Health Care Facility Stay tape -- contains information collected on reports of stays in hospitals and non-hospital health care facilities (e.g., nursing home, mental health care facility) as well as information abstracted from facility medical records. This fourth file, originally titled the Health Care Facility Record Data Tape and released in 1987, has been substantially revised. The revised tape contains 25,436 health care facility stay records for 8,270 subjects. The tape is described in detail in the following pages. Description of Tape Revision The 1982-84 Health Care Facility Record tape has been restructured to produce the Revised 1982-84 Health Care Facility Stay Data Tape. The original file contained only the coded medical abstracts obtained from health care facilities. However, the Health Care Facility Stay data files produced for the 1986 and 1987 followups include both the descriptive information reported by the respondent and the medical information returned from the health care facility. This new format includes information about all possible stays in health care facilities whether or not an actual health care facility record was obtained. It was created to facilitate the use of the health care facility data. At the time that the 1986 and 1987 Health Care Facility Stay files were constructed, a comparable 1982-84 Health Care Facility Stay file did not exist. However, it has been possible to reconstruct such a file for 1982-84 because most of the information needed to replicate the content and proces- sing of the 1986 and 1987 files was available. The 1982-84 interview con- tained detailed reports of the conditions leading to each stay in a health care facility, the dates of each stay and the names of the facilities where the stays occurred. This information could be linked to the medical records that were obtained from the facilities and which appeared on the 1982-84 Health Care Facility Record file as it was originally released. In addition, during data collection for the 1986 and 1987 files, additional medical records for the 1982-84 followup period were obtained. These have been included in the revised file. The resulting data set is more complete than the original; it can be used in conjunction with Facility Stay files for later followup periods; and it provides information on stays in health care facilities that were reported but not confirmed by the receipt of a facility abstract. The Revised 1982-84 NHEFS Health Care Facility Stay (HCFS) file contains information on all overnight health care facility stays for members of the 1982-84 followup cohort. The 1982-84 Followup cohort consisted of the 14,407 subjects who were between 25 and 74 years old at their NHANES I examination. Followup cohort members who have either an interview or a death certificate on the 1982-84 NHEFS data files or who returned a mail questionnaire were eligible for the health care facility records component. The aim of this component was to present a complete set of health care facility (i.e., hospital and nursing home) records for each 1982-84 Followup cohort member. These records are intended to cover the period from the NHANES I examination to the date of the 1982-84 interview for surviving subjects and the period from exam to the date of death for deceased subjects. This is referred to as the "in-scope" period. Stays that were reported prior to or after the in- scope period were defined as out-of-scope for the 1982-84 followup. The procedures for constructing this file are briefly described below. Restructuring the 1982-84 Health Care Facility Record File: When the 1986 NHANES I Epidemiologic Followup was designed, it was decided to combine the information which respondents reported concerning overnight health care facility stays with the abstracted information received from the facilities. The resulting file was built using a computerized tracking system. In order to reprocess the 1982-84 data file and make it comparable with the 1986 format, it was necessary to review the 1982-84 interviews and enter the data into the tracking system developed for the 1986 wave. Abstracts that had been received during the 1982-84 followup were matched to the interview information that had been entered into the tracking system in the same manner as the 1986 and 1987 abstracts were being matched to inter- view information. The results of the matching process were then used to build the revised 1982-84 file. Occasionally, facilities which were being contacted as part of the 1986 or 1987 followups would send abstracts for stays that had been reported in the 1982-84 followup, but for which an abstract had not been received during the appropriate collection period. These abstracts were also entered into the tracking system. The resulting restructured file was renamed the Revised 1982-84 Health Care Facility Stay file and is comparable in format to the 1986 to 1987 Health Care Facility Stay files. Matching Records: When the abstracts were reviewed, they were checked against report informa- tion in the tracking system to determine if the abstract "matched" any of the reported stays. Date of admission and diagnosis were used as matching criteria but exact matches on date or diagnosis were not required for a stay to be considered matched. Abstracts were matched to reports if the reported date of admission was within a year of the actual date of admission and if the reported reason for admission involved the same body system as at least one of the diagnoses present on the abstract. Cases that did not meet these specific criteria were reviewed by NCHS staff and matched when appropriate. Since the matching rules allowed for an admission date of up to one year before or after the reported date of admission, some stay records are present on the file with an out-of-scope report date, but an in-scope date on the matched abstract. These records are identified by a Type C flag in position 199 of the record (see further explanation of the Type C flag below). Each record on the file represents an overnight facility stay. Therefore, one or more records will exist for some 1982-84 Followup cohort subjects, while other subjects will have no records on the file. The structure of the data file reflects the system used to obtain and process stay information. The record is divided into four major sections: 1) the report section, 2) the record status section, 3) the abstract section, and, 4) the related stay section. An example of the record layout is provided in figure 1. The subject identification number (i.e., the sample sequence number) is in positions 1-5 on each record. This number is unique for each subject and is used when linking the Health Care Facility Stay tape to all other NHEFS and NHANES I Public Use Data Tapes. The total number of records per subject is found in positions 6-7 on the file. The first section of the record is the report section (positions 29-59 and 63-204) which contains information from the reporting source as well as stay identification numbers assigned by NCHS. Each stay entered into the report section is assigned a health care facility stay id number (positions 29-33). When used in conjunction with the sample sequence number, this number uniquely identifies each record on the file. The reported date of admission is found in positions 47-54. This date is used in conjunction with the date of exam to determine whether reported stays were in-scope for the NHEFS 1982-84 survey (position 199). The record status section (positions 60-62) contains a code for the result of the abstract review i.e., match or non-match status. If there existed an abstract that matched a report then a record status code of MAT (match) was assigned. An abstract that did not match any report but was in-scope for the 1982-84 survey period was assigned the record status code of ASF (additional stay found). If no matching abstract was found, the appropriate non-match code was assigned. The abstract section (positions 205-379) contains the information obtained from the facility records including actual dates of admission, discharge and diagnoses. The diagnoses on the abstracts were coded using the ICD-9-CM according to the medical coding specifications detailed in the following section of this codebook. The abstract section of each record is similar to the original 1982-84 NHEFS Health Care Facility record file released in August 1987. The other three sections are those that were added for compar- ability with the 1986 and 1987 HCFS files. Information will be present in one or more sections of the record depending on whether a report was obtained, and whether an abstract was received. The presence or absence of information in the first three sections results in three different record profiles. Figure 2 illustrates these three profiles. The first is the successfully matched stay record, where an abstract was received which matched a report. Abstract information is added to the report and the code of MAT was entered into the record status section. Complete information is available in the first three sections of the record for these stays. The second type occurs when an abstract was not matched to a report and, therefore, no data is contained in the abstract section. The appropriate non-match code was entered in the record status section. The third type of record is one which was generated solely by the existence of a facility abstract. This type of record resulted from an existing in-scope abstract that did not match with any report on the tracking system. When this occurred, the abstract was entered on the file, and stay identifiers were assigned in the report section of the record but no other information in the report section is present. An ASF (additional stay found) code was entered in the record status section. In some cases requests were made to facilities for information about stays with reported admission dates that preceded the date of the NHANES I exam (i.e., were out-of-scope). This was done to maximize the collection of reports of hospital or nursing home stays. Reports of stays with a reported date of admission more than one year prior to the exam were retained on the file when they represented the only mention of visits to a specific health care facility for a given subject. These were flagged with a Type D in position 199. All stays with reported dates within the year immediately preceding the exam were kept and flagged with a Type C in position 199. After the receipt of information from the health care facility, it was necessary to remove stays from the tracking system that had been out-of-scope and to incorporate information on in-scope stays that was generated from the "out-of-scope" reports. If an in-scope abstract was received from a facility named on a Type D report, the in-scope abstract was added to the file with a record status code of ASF and the Type D report was deleted from the file. The Type D report was also deleted from the file if the facility responded to the Type D request, but sent no in-scope abstracts. In this case it was presumed that the respondent had correctly reported the date as out-of-scope. In 47 cases the Type D reports remain on the final version of the file. This occurred when it had been impossible to contact the facility or when authorization to obtain hospital records had not been granted. These records for unconfirmed reports of out-of-scope stays can be eliminated from analyses at the analysts' discretion. In the case of Type C reports, if an in-scope abstract was returned which matched the Type C report, the report was assigned a record status code of MAT (n=144). (Recall the matching rules permitted an admission date of up to one year before or after the reported date of admission.) If the facility responded but no in-scope abstract was received, the Type C report was removed from the file. Again it was assumed that the correct date had been reported and the stay was truly out-of-scope. There are 42 Type C reports that remain on the file. These reports were given by respondents who did not grant permission to obtain abstracts or they involved facilities that could not be contacted, refused to participate or did not respond. These unconfirmed reports of out-of-scope stays are identified by the non-match status in positions 60-62 and a Type C flag in position 199. The final section of the record contains related stay codes (positions 380- 429). These related stay codes are used to identify stays which are contained within other stays. This occurred most often when nursing home residents had a brief hospital stay but then returned to the nursing home. A detailed example of the related stay section is presented below. In panel A, a chronologic history of a subject's hospital and nursing home stays is presented in order to facilitate the discussion of the related stay codes. This subject was admitted to the nursing home on March 1, 1981, and discharged to the hospital on April 1, 1981. He returned to the original nursing home on April 8 and stayed until April 22 when he required readmis- sion to the hospital. He returned from the hospital to the nursing home on April 25, 1981 where he remained until April 30, 1981. Panel A: Chronologic profile of hospital and nursing home stays: Location Admission Discharge Nursing home 03/01/81 04/01/81 Hospital 04/01/81 04/08/81 Nursing home 04/08/81 04/22/81 Hospital 04/22/81 04/25/81 Nursing home 04/25/81 04/30/81 Panel B illustrates how these stays are present in the final file. The three nursing home stays were collapsed into one long stay with two related hospitalizations. The related stay codes were added to demonstrate the relationship between the hospital and nursing home stays. Panel B: Final file layout Variable Position: 29-33 209 210-215 216-221 380-384 385-389 Variable Name: Stay Dis- First Second Number Type Admit charge Related Related 10201 N. Home 03/01/81 04/30/81 10101 10102 10101 Hosp. 04/01/81 04/08/81 10201 10102 Hosp. 04/22/81 04/25/81 10201 Medical Coding Specifications Medical coding for the NHEFS 1982-84 data tape was based on the International Classification of Diseases-9th Revision-Clinical Modification (ICD-9-CM). The health care facility was asked to abstract all diagnoses and procedures onto a special form. In most cases, a copy of the hospital discharge summary and/ or medical records facesheet was attached to the abstract. The diagnoses and procedures listed on the discharge summary or facesheet were then compared with those provided by coding the diagnoses or procedures as provided on the discharge summary or the facesheet. All diagnoses were coded to the highest level of specificity possible. The fourth-digit subcategory for diagnosis and procedure codes was used whenever possible. The fifth-digit subclassification of disease for diagnosis codes was also used when appropriate. A three-digit ICD code was used only if it could not be further subdivided. The following rules were used to code diagnoses and procedures. Rules Governing Medical Coding of Diagnoses: All medical diagnoses listed on the health care facility abstract form or the discharge summary are coded in the order in which the diagnoses were listed. The principal diagnosis is the condition established after study to be chiefly responsible for occasioning the admission of the patient to the health care facility. The admitting diagnosis is not used as the principal diagnosis unless the admitting and discharge diagnoses are the same. Ex: Patient admitted with a diagnosis of bronchopneumonia. After workup and treatment, x-ray findings, etc., the patient was discharged with a final diagnosis of bronchopneumonia. The principal diagnosis is coded 485 for bronchopneumonia. Note that the facility was asked to select the principal diagnosis and not review of the records was made to determine if the current diagnosis was selected. All other diagnoses or conditions existing at the time of admission or that developed subsequently during the stay are coded. Ex: Patient was admitted with a diagnosis of uncontrolled diabetes mellitus, and during the course of examination and treatment, phlebitis was discovered. The diabetes and the phlebitis are coded. Diagnoses documented as probable, possible, suspected, question of, sug- gestive of, compatible with, or questionable are coded and prefixed with a "P". Ex: If the diagnosis is stated possible myocardial infarction, the diagnosis code is P410.9. If a diagnosis is stated as "rule out" or "R/O", the condition is coded as if it exists and the "P" prefix is not used. If a diagnosis is stated as "ruled out", the condition is not coded. Ex: If "R/O M.I." appears on the facesheet, the code is 410.9. If "M.I. ruled out" appears, the condition is not coded. When the abstract included an infarction as one of the discharge diagnoses and it was clear from other information in the abstract or the final diagnoses sections of the facesheet and discharge summary that the infection was a result of a hospital procedure, the appropriate external cause of injury code was added. Malignant neoplasms are coded according to ICD-9-CM coding specifications which indicate primary site of origin. Injuries and poisonings are coded, where applicable, using both the nature of the injury and the external cause of injury code (E800-E999). Ex: Patient sustained comminuted fracture of the femur due to a fall down stairs. Nature of injury code is 821.00 and external cause of injury code is E880.9. "History of" conditions are not coded with the following exceptions: Old myocardial infarction (more than 8 weeks since last occurrence) Status post bypass surgery Malignant neoplasm (cancer in remission or under treatment) Old cerebrovascular accident Sterilization Normal pregnancy undelivered Manipulation of an IUD These diagnoses are coded using "V" codes and were used on a limited basis. Recurrent malignancy codes are prefixed with an "R". Symptoms (ICD-9-CM) codes 7800-7999) were coded using the following guidelines: 1. When the only diagnosis listed on the abstract form, facesheet, and/or discharge summary is a symptom, the symptom is coded. Ex: The only discharge diagnosis listed is "chest pain". The code number 786.50 (chest pain, unspecified) is assigned. 2. When a symptom is listed that is unrelated to any of the diag- noses listed, the symptom is coded. Ex: The discharge diagnoses listed are acute myocardial infarction, diabetes mellitus, and hepatomegaly. The hepato- megaly is also coded. 3. When a symptom is listed and is related to a listed discharge diagnosis the symptom is not coded. Ex: The discharge diagnoses listed are diabetes mellitus, acute appendicitis, severe abdominal pain. Only the diabetes and the appendicitis are coded. The abdominal pain is not coded. Rules Governing Medical Codes for Procedures: The same general rules apply to coding procedures as to coding diagnoses. Medical procedures are coded and sequenced in accordance with the principal and secondary procedures described on the health care facility abstract form or the discharge summary/facesheet. The principal procedure is the primary procedure most related to the princi- pal diagnosis and is performed for definitive treatment as opposed to diag- nostic and/or exploratory purposes. Ex: Diagnosis = uterine fibroids. Procedures = biopsy of uterus, total abdominal hysterectomy, incidental appendectomy. The hysterectomy is coded as the principal procedure and the appendectomy and the biopsy are coded as secondary procedures. All procedures documented on the discharge summary and/or facesheet are coded if they fall into the following categories: Biopsies (if related to the principal diagnosis and procedure or if related to the other listed diagnoses) Surgical procedures Cardiac catheterizations D and C (following delivery or abortion only) The following procedures are not coded: Surgical approach Operative cholangiogram Lumbar puncture CT scan Endoscopy Diagnostic D and C Diagnostic radiology Examination (under anesthesia, physical exam, etc.) Manipulations Physical therapy Application or removal of casts, splints, etc. Medical Coding Conventions: Diagnostic codes--Up to ten diagnoses are coded for each hospital and nursing home stay. The format for each diagnosis code is six positions. The following conventions were used when entering diagnostic codes on the data tape: 1. ICD-9-CM diagnostic codes (including "V" codes) were entered beginning with the second position of the variable field continuing through the sixth position. There is an implied decimal point between the fourth and fifth positions of the variable field. 2. If the diagnoses codes required less than five digits the remaining tape positions are blank. 3. Prefix codes "P" and "R" are coded in the first tape position. If the diagnosis code has no prefix the first position is blank. Ex. 1: _ 4 2 2 9 0 Code is 422.90 Ex. 2: V 7 1 1 Code is V71.1 Ex. 3: 4 3 6 Code is 436 Ex. 4: P 1 8 0 0 Code is P180.0 Ex. 5: R 1 7 4 9 Code is R174.9 4. E codes - External cause of injury codes An external cause of injury code is provided, when applicable, immediately after the medical diagnosis code which describes the nature of the injury. E codes were entered on the data tape beginning in the first position of the variable field and continuing through the fifth position. There is an implied decimal point between the fourth and fifth positions of the variable field. If an E code required less than five positions the remaining positions are blank. If an E code is not applica- ble (i.e., the medical diagnosis code is not a nature of injury code) or could not be coded, the variable field is blank. Ex. 1: E 9 0 6 1 Code is E906.1 Ex. 2: E 8 5 1 Code is E851 Procedure codes--Up to five procedures are coded for each health care facili- ty record. Each procedure code is formatted in a field containing four positions. Procedure codes were entered beginning with the first positions. Procedure codes were entered beginning with the first position of the varia- ble field continuing through the fourth position. There is an implied deci- mal point between the second and third positions of the variable field. If a procedure code required less than four positions the remaining positions are blank. Ex. 1: 4 2 9 2 Code is 42.92 Ex. 2: 0 3 1 Code is 03.1 RECORD LAYOUT Stay Tape Codebook Tape Position Frequencies Variable Description and Codes (1-28) SUBJECT INFORMATION 1-5 25,436 NHANES I Sample Sequence Number 6-7 Record Count 25,436 01-55 = Total number of records Note: Each record on the file represents an overnight stay in a health care facility (hospi- tal or nursing home). This variable identifies for each subject the total number of records on the file. It will be the same for each record the subject has on the file. 8-28 25,436 Blank (29-59, STAY IDENTIFIERS AND REPORTED 63-204) INFORMATION ON FACILITY STAYS Note: The report section of the record (posi- tions 29-59 and 63-204) contains the information on health care facility stays that was reported on the questionnaire, on a death certificate, on another hospital/nursing home abstract form, or obtained from other sources. (29-33) Health Care Facility Stay ID Number Note: When used in conjunction with the sample sequence number this number uniquely identifies each record on the tape. It is composed of three variables: Survey Period Identifier, Facility Number and Stay Number Within Facility. For example: a Stay Number of 10102 refers to a facility stay reported during the NHEFS 1982-84 wave (1) in the first facility reported for that subject (01) but the second admission to that facility (02). 29 Survey Period Identifier 25,436 1 = NHEFS 1982-84 Note: For each NHEFS subject, a two digit num- ber was assigned to each facility in which a stay occurred. Thus, if a subject had multiple stays at the same facility, all stays will have the same facility number. Facility numbers were assigned consecutively. However, due to tape editing, there are missing numbers in the sequence of facility numbers. 30-31 Facility Number 25,436 01-09 = Hospital/nursing home number Note: For each NHEFS subject, a two digit number was assigned to each facility in which a stay occurred. Thus, if a subject had multiple stays at the same facility, all stays will have the same facility number. Facility numbers were assigned consecutively. However, due to tape editing, there are missing numbers in the sequence of facility numbers. 32-33 Stay Number Within Facility 25,436 01-45 = Stay number 00 = D stay record Note: The two digit stay numbers were assigned to identify different stays in the same facili- ty. Type D stay records were assigned a stay number of "00". A type D stay record is defined as a stay with a reported admission date more than one year prior to the date of the NHANES I Examination (see position 199). Stay numbers within facilities were assigned consecutively. However, due to tape editing, three are missing numbers in the sequence of stay numbers within facilities. 34-35 Facility ID Profile 24,457 01 = Hospital 664 02 = Nursing home 315 03 = Out of country, don't know, or not ascertained Note: This variable identifies the type of facility to which the request for a stay record was mailed. 36-46 25,436 Blank (47-54) Reported Admission Date/Range Respondents were asked to provide information on the month, day and year of admission for each stay to a facility. A range of years was coded when the respondent was unable to recall the exact year of admission. When the year of admission was reported as a range, the beginning year of the range is found in positions 51-52 and the ending year of the range is found in positions 53-54. Except for type D (position 199) records the reported date of admission is present for all source code 2 and 4 records (see position 200). 47-48 Reported Month of Admission 1,136 01-12 = Month of admission 4 98 = Don't know 18,453 99 = Not ascertained 5,843 Blank = Type D (position 199), record status code ASF (positions 60-62), or source code 1 or 3 (positions 200) 49-50 Reported Day of Admission 188 01-31 = Day of admission 3 98 = Don't know 19,402 99 = Not ascertained 5,843 Blank = Type D (position 199), record status code ASF (positions 60-62), or source code 1 or 3 (position 200) Tape Position Frequencies Variable Description and Codes 51-52 Reported Year of Admission or Beginning Year of Range 18,973 68-84 = Year of admission or beginning year of range (1968-1984) 505 98 = Don't know 115 99 = Not ascertained 5,845 Blank = Type D (position 199), record status code ASF (positions 60-62), or source code (position 200) 1 or 3 53-54 Reported Year of Admission - Ending Year of Range 1,452 70-84 = Ending year of range (1970-1984) 23,984 Blank = No range given for reported year of admission, type D (position 199), record status code ASF (positions 60-62), or source code (position 200) 1 or 3 55-59 25,436 Blank (60-62) RECORD STATUS Note: The record status section of the record (positions 60-62) contains information on the outcome of the request for a health care facili- ty stay. 60-62 Record Status Code Note: See Appendix A for an explanation of the record status codes. 25,436 ANO - XRD = Record status code (63-198) Reported Conditions and Codes During the process of completing the Hospital and Health Care Facility Chart (HHCF) respon- dents described the conditions that led to their overnight facility stays. This information is included as a text field on the stay record. Space is allotted for the recording of up to four reasons for the hospital or nursing home stay (see positions 67-96, 101-130, 135-164 and 169-198). A numeric code was assigned to each text description to aid the researcher in the use of this information (see positions 63-66, 97-100, 131-134, 165-168). These variables should be used in conjunction with information in the abstract section, i.e., ICD-9-CM diagnosis codes, present on records with a record status code of MAT or ASF. Appendix B contains a com- plete description of these fields along with guidelines for their use. (63-96) First Reported Condition 63-66 Condition Code 19,388 01-37 = Condition code (See Appendix B) 6,048 Blank = Source Code not equal to 4, D stay record, or Record Status Code ASF. 67-96 Condition Text 19,388 Description of reason for facility stay 6,048 Blank = Source Code not equal to 4, D stay record, or Record Status Code ASF (97-130) Second Reported Condition 97-100 Condition Code 5,748 01-37 = Condition code (See Appendix B) 19,688 Blank = Source Code not equal to 4, D stay record, or Record Status Code ASF, or only one condition reported. Tape Position Frequencies Variable Description and Codes 101-130 Condition Text 5,748 Description of reason for facility stay 19,688 Blank = Source Code not equal to 4, D stay record or Record Status Code ASF, or only one condition reported. (131-164) Third Reported Condition 131-134 Condition Code 1,346 01-37 = Condition code (See Appendix B) 24,090 Blank = Source Code not equal to 4, D stay record or Record Status Code ASF, or less than three conditions reported. 135-164 Condition Text 1,346 Description of reason for facility stay 24,090 Blank = Source Cod not equal to 4, D stay record or Record Status Code ASF, or less than three conditions reported. Tape Tape Position Frequencies Variable Description and Codes (165-198) Fourth Reported Condition 165-168 Condition Code 288 01-37 = Condition code (See Appendix B) 25,148 Blank = Source code not equal to 4, D stay record or Record Status Code ASF, or less than four conditions reported. 199 Type of Stay Flag 186 C = A reported stay with admission date up to one year prior to the date of NHANES I Examination. 47 D = A reported stay with admission date more than one year prior to date of NHANES I exam. If there were multiple reported stays in the same facility that were all type D (more than one year prior to exam) these stays were consolidated into one entry in the tracking system. If an in- scope abstract was received in response to a type D report, the abstract was never matched to the type D report, but was assigned a record status code of ASF (positions 60-62). The type D report was then removed from the file. The 47 type D reports that remain on the file were unable to be resolved either because the facility could not be contacted (status of FNC) or because authorization to collect facility data was not obtained (status of ANO). 25,203 Blank = In-scope stay; a reported date of admission after the exam date. This field is also blank for records with status codes of ASF. Note: This variable identifies reported facility stays as in-scope or out-of-scope for the NHEFS 1982-84 interview period. Reported dates of admission of don't know (989898) or not ascertained (999999) in positions 47-52 were considered in-scope. 200 Source of Report of Stay that Initiated Request for Abstract 126 1 = Information from death certificate 205 2 = Information from hospital abstract report 141 3 = Information from other source 19,435 4 = Information from NHEFS 1982-84 interview 5,529 Blank = Not a requested stay. Additional stay information obtained from facility (record status code ASF positions 60 -62). ASF may also be coded as source code 3. Tape Position Frequencies Variable Description and Codes 201-204 25,436 Blank (205-379) ABSTRACT DATA Note: The abstract data portion of the record (positions 205-379) contains information ob- tained from an abstract form returned by the facility. This section of the stay record (excluding positions 207-208) will be blank when a facility did not return an abstract form for a stay (n=6933). 205-206 Abstract Number 18,503 01-53 = Number of abstract 6,933 Blank = Stay reported, no abstract form received Note: For each subject, a two digit number was assigned consecutively to each abstract form received. 207-208 Total Number of Abstracts Received 25,436 00-53 = Total number of abstracts received Note: This number represents the total number of abstracts received for each subject. The total number is repeated on each subject record. 209 Facility Record Type 18,085 1 = Hospital 418 2 = Nursing home 6,933 Blank = Stay reported, no abstract form received (210-215) Date of Admission 210-211 Month of Admission 18,501 01-31 = Day of admission 6 99 = Not ascertained 6,933 Blank = Stay reported, no abstract form received 212-213 Day of Admission 18,497 01-31 = Day of admission 6 99 = Not ascertained 6,933 Blank = Stay reported, no abstract form received 214-215 Year of Admission 18,503 71-84 = Year of admission (1971-1984) 6,933 Blank = Stay reported, no abstract form received (216-221) Date of Discharge Note: When a subject had a brief break in a nursing home stay, the nursing home stays were combined into one long stay with the latest discharge date assigned to the stay. The information contained in the report and abstract sections of the stay is from the earliest abstract. For example: subject A was in a nursing home from 10-31-81 to 12-22-81. The subject was readmitted to the same nursing home 1-3-82. These 2 stays would appear on the file as 1 stay from 10-31-81 to 3-5-82. Length of stay would be calculated on the entire stay (see positions 222-225). If the break in the nursing home was due to an interspersed hospitalization, the nursing home stays were collapsed as described above and a code was entered in the related stay section (see positions 380-429). 216-217 Month of Discharge 18,350 01-12 = Month of discharge 145 97 = Inapplicable (still at facility on date of 1982-84 interview) 8 99 = Not ascertained 6,933 Blank = Stay reported, no abstract from received 218-219 Day of Discharge 18,346 01-31 = Day of discharge 145 97 = Inapplicable (still at facility on date of 1982-84 interview) 12 99 = Not ascertained 6,933 Blank = Stay reported, no abstract form received 220-221 Year of Discharge 18,353 71-84 = Year of discharge (1971-1984) 145 97 = Inapplicable (still at facility on date of 1982-84 interview) 5 99 = Not ascertained 6,933 Blank = Stay reported, no abstract form received 222-225 Length of Record Stay 80 0000 = Died on day of admission 18,243 0001-3380 = Total number of days in facility 145 9997 = Inapplicable (still at facility on date of 1982-84 interview) 15 9999 = Not ascertained 6,933 Blank = Stay reported, no abstract form received Note: Length of stay is calculated by subtract- ing the date of admission from the date of dis- charge. For subjects with nursing home stays, brief breaks were collapsed into one continuous nursing home stay (see positions 216-221). For subjects with information coded in the related stays section (see positions 380-429) length of stay will include time spent in other facili- ties. Length of stay is not ascertained if either the admission or discharge date contains a code of 99. 226 Was the Patient in Cardiac Intensive Care Unit? 1,124 1 = Yes 15,811 2 = No 418 7 = Inapplicable (facility is a nursing home) 1,150 9 = Not ascertained 6,933 Blank = Stay reported, no abstract form received 227-229 Number of Days in Cardiac Intensive Care Unit 1,053 000-076 = Number of days 17,379 997 = Inapplicable (position 226 = 2,7,or 9) 71 999 = Not ascertained 6,933 Blank = Stay reported, no abstract form re- ceived Note: A length of stay of 0 days occurred when a subject was admitted to the CCU and was dis- charged on the day of admission. 230 Was the Patient In Other Intensive Care Unit? 877 1 = Yes 14,979 2 = No 418 7 = Inapplicable (facility is a nursing home) 2,229 9 = Not ascertained 6,933 Blank = Stay reported, no abstract form received 231-233 Number of Days in Other Intensive Care Unit 832 000-129 = Number of days 17,626 997 = Inapplicable (Position 230 = 2,7,or 9) 45 999 = Not ascertained 6,933 Blank = Stay reported, no abstract form received Note: A length of stay of 0 days occurred when a subject was admitted to the ICU and was dis- charged on the day of admission. 234 Patient Admitted to Nursing Home From: 99 1 = Private residence 235 2 = Acute care hospital 8 3 = Chronic disease hospital 58 4 = Other nursing home 18,085 7 = Inapplicable (facility is a hospital) 18 9 = Not ascertained 6,933 Blank = Stay reported, no abstract form received 235 Disposition of Hospital Patient 15,819 1 = Routine discharge/discharged home 70 2 = Left against medical advice 883 3 = Discharged/transferred to another faci- lity or organization 215 4 = Discharged/referred to organized home care service 729 5 = Died 15 6 = Not discharged/still in hospital on the date of 1982-84 interview 418 7 = Inapplicable (facility is a nursing home) 354 9 = Subject discharged, disposition not ascertained 6,933 Blank = Stay reported, no abstract form received 236 Disposition of Nursing Home Patient 130 1 = Not discharged/still in a nursing home on date of 1982-84 interview 23 2 = Discharged to private residence/referral to organized home care services 122 3 = Died 59 4 = Discharged to private residence/no re- ferral 81 5 = Transferred to another facility 18,085 7 = Inapplicable (facility is a hospital) 3 9 = Not ascertained 6,933 Blank = Stay reported, no abstract form received 237 Transferred to Another Health Care Facility 41 1 = Acute care hospital 32 2 = Another nursing home 0 3 = Chronic disease hospital 5 4 = Other 18,422 7 = Inapplicable (Position 236 = 1, 2, 3, 4, 7, or 9) 3 9 = Not ascertained 6,933 Blank = Stay reported, no abstract form received 238-239 Number of Diagnoses 18,493 01-21 = Number of diagnoses 10 99 = Not ascertained 6,933 Blank = Stay reported, no abstract form received Note: This variable identifies the total number of diagnoses entered on the abstract. The num- ber of coded diagnoses may exceed the maximum number (10) allowed on the data tape. 240-245 Principal Diagnosis 18,493 ICD-9-CM Code 10 999999 = Not ascertained 6,933 Blank = Stay reported, no abstract form re- ceived Note: See medical coding specifications. 246-250 Principal Diagnosis E Code 1,380 ICD-9-CM Code 24,056 Blank = Stay reported, no abstract form received or principal diagnosis does not require E code Note: See medical coding specifications Tape Position Frequencies Variable Description and Codes 251-256 Second Diagnosis 13,083 ICD-9-CM Code 5,420 999997 = Inapplicable (only one diagnosis coded) 6,933 Blank = Stay reported, no abstract form re- ceived Note: See medical coding specifications. 257-261 Second Diagnosis E Code 376 ICD-9-CM Code 5,420 99997 = Inapplicable (only one diagnosis coded) 19,640 Blank = Stay reported, no abstract form received or second diagnosis does not require E code Note: See medical coding specifications. 262-267 Third Diagnosis 8,552 ICD-9-CM Code 9,951 999997 = Inapplicable (less than three diagnoses coded) 6,933 Blank = Stay reported, no abstract form received Note: See medical coding specifications. 268-272 Third Diagnosis E Code 214 ICD-9-CM Code 9,951 99997 = Inapplicable (less than three diagnoses coded) 15,271 Blank = Stay reported, no abstract form received or third diagnosis does not require E code Note: See medical coding specifications. 273-278 Fourth Diagnosis 5,420 ICD-9-CM Code 13,083 999997 = Inapplicable (less than four diagnoses coded) 6,933 Blank = Stay reported, no abstract form received Note: See medical coding specifications. 279-283 Fourth Diagnosis E Code 163 ICD-9-CM Code 13,083 99997 = Inapplicable (less than four diagnoses coded) 15,271 Blank = Stay reported, no abstract form received or fourth diagnosis does not require E code Note: See medical coding specifications. 284-289 Fifth Diagnosis 3,300 ICD-9-CM Code 15,203 999997 = Inapplicable (less than five diagnoses coded) 6,933 Blank = Stay reported, no abstract form received Note: See medical coding specifications. 290-294 Fifth Diagnosis E Code 100 ICD-9-CM Code 15,203 99997 = Inapplicable (less than five diagnoses coded) 10,133 Blank = Stay reported, no abstract form received or fifth diagnosis does not require E code Note: See medical coding specifications. 295-300 Sixth Diagnosis 1,956 ICD-9-CM Code 16,547 999997 = Inapplicable (less than six diagnoses coded) 6,933 Blank = Stay reported, no abstract form received Note: See medical coding specifications. Tape Position Frequencies Variable Description and Codes 301-305 Sixth Diagnosis E Code 72 ICD-9-CM Code 16,547 99997 = Inapplicable (less than six diagnoses coded) 8,817 Blank = Stay reported, no abstract form received or sixth diagnosis does not require E code Note: See medical coding specifications. 306-311 Seventh Diagnosis 1,039 ICD-9-CM Code 17,464 999997 = Inapplicable (less than seven diagnoses coded) 6,933 Blank = Stay reported, no abstract form received Note: See medical coding specifications. 312-316 Seventh Diagnosis E Code 37 ICD-9-CM Code 17,464 99997 = Inapplicable (less than seven diagnoses coded) 8,817 Blank = Stay reported, no abstract form received or seventh diagnosis does not require E code Note: See medical coding specifications. 317-322 Eighth Diagnosis 568 ICD-9-CM Code 17,935 999997 = Inapplicable (less than eight diagnoses coded) 6,933 Blank = Stay reported, no abstract form received Note: See medical coding specifications. 323-327 Eighth Diagnosis E Code 12 ICD-9-CM Code 17,935 99997 = Inapplicable (less than eight diagnoses coded) 8,817 Blank = Stay reported, no abstract form received or eighth diagnosis does not require E code Note: See medical coding specifications. 328-333 Ninth Diagnosis 310 ICD-9-CM Code 18,193 999997 = Inapplicable (less than nine diagnoses coded) 6,933 Blank = Stay reported, no abstract form received Note: See medical coding specifications. 334-338 Ninth Diagnosis E Code 9 ICD-9-CM Code 18,193 99997 = Inapplicable (less than nine diagnoses coded) 7,234 Blank = Stay reported, no abstract form received or ninth diagnosis does not require E code Note: See medical coding specifications. 339-344 Tenth Diagnosis 165 ICD-9-CM Code 18,338 999997 = Inapplicable (less than ten diagnoses coded) 6,933 Blank = Stay reported, no abstract form received Note: See medical coding specifications. 345-349 Tenth Diagnosis E Code 2 ICD-9-CM Code 18,338 99997 = Inapplicable (less than ten diagnoses coded) 7,096 Blank = Stay reported, no abstract form received or tenth diagnosis does not require E code Note: See medical coding specifications. 350-351 Number of Procedures 18,085 00-05 = Number of procedures 418 97 = Inapplicable (facility is a nursing home) 6,933 Blank = Stay reported, no abstract form received Note: This variable identifies the total number of procedures coded on the facility abstract. Tape Position Frequencies Variable Description and Codes 352-355 First Procedure 7,264 ICD-9-CM Code 11,239 9997 = Inapplicable (facility is a nursing home or no procedures coded) 6,933 Blank = Stay reported, no abstract form received Note: See medical coding specifications. 356-359 Second Procedure 2,635 ICD-9-CM Code 15,868 9997 = Inapplicable (facility is a nursing home or only one procedure coded) 6,933 Blank = Stay reported, no abstract form received Note: See medical coding specifications. 360-363 Third Procedure 774 ICD-9-CM Code 17,729 9997 = Inapplicable (facility is a nursing home or less than three procedures coded) 6,933 Blank = Stay reported, no abstract form received Note: See medical coding specifications. 364-367 Fourth Procedure 234 ICD-9-CM Code 18,269 9997 = Inapplicable (facility is a nursing home or less than four procedures coded) 6,933 Blank = Stay reported, no abstract form received Note: See medical coding specifications. 368-371 Fifth Procedure 55 ICD-9-CM Code 18,448 9997 = Inapplicable (facility is a nursing home or less than five procedures coded) 6,933 Blank = Stay reported, no abstract form received Note: See medical coding specifications. (372-373) Presence of Documents 372 Pathology Report 560 1 = Required and present 119 2 = Required and not present 17,406 6 = Not required 418 7 = Inapplicable (facility is a nursing home) 6,933 Blank = Stay reported, no abstract form received 373 Third Day EKG Report 377 1 = Required and present 151 2 = Required and not present 17,557 6 = Not required 418 7 = Inapplicable (facility is a nursing home) 6,933 Blank = Stay reported, no abstract form received 374-379 25,436 Blank Tape (380-429) RELATED STAY CODES Note: Residents in nursing homes are often admitted to hospitals during the course of their stays in the nursing home. The related stay section of the record cross-links nursing home stays with interspersed hospital stays. In the case of nursing home records, this set of variables identifies hospital stays that occur- red during the nursing home stay. Up to 10 rel- ated stays can be listed. In the case of hospital records, this set of variables identifies the nursing home stay with- in which the hospital stay occurred. The Related Stay is identified by the Health Care Facility Stay ID Number (positions 29-33) of that stay. An example of the usage of the related stay sec- tion is found in the introduction to this code- book. (380-384) ID of First Related Stay 380 Survey Period Identifier 231 1 = NHEFS 1982-84 25,205 Blank = No related stays 381-382 Facility Number 231 01-07 = Hospital/nursing home number 25,205 Blank = No related stays 383-384 Stay Number Within Facility 231 01-20 = Stay number 25,205 Blank = No related stays (385-389) ID of Second Related Stay 385 Survey Period Identifier 34 1 = NHEFS 1982-84 25,402 Blank = No second related stay 386-387 Facility Number 34 01-07 = Hospital/nursing home number 25,402 Blank = No second related stay 388-389 Stay Number Within Facility 34 01-18 = Stay number 25,402 Blank = No second related stay (390-394) ID of Third Related Stay 390 Survey Period Identifier 15 1 = NHEFS 1982-84 25,421 Blank = No third related stay 391-392 Facility Number 15 02-07 = Hospital/nursing home number 25,421 Blank = No third related stay 393-394 Stay Number Within Facility 15 01-11 = Stay number 25,421 Blank = No third related stay (395-399) ID of Fourth Related Stay 395 Survey Period Identifier 6 1 = NHEFS 1982-84 25,430 Blank = No fourth related stay 396-397 Facility Number 6 02-03 = Hospital/nursing home number 25,430 Blank = No fourth related stay 398-399 Stay Number Within Facility 6 01-07 = Stay number 25,430 Blank = No fourth related stay (400-404) ID of Fifth Related Stay 400 Survey Period Identifier 25,436 Blank = No fifth related stay Tape Position Frequencies Variable Description and Codes 401-402 Facility Number 25,436 Blank = No fifth related stay 403-404 Stay Number Within Facility 25,436 Blank = No fifth related stay (405-409) ID of Sixth Related Stay 405 Survey Period Identifier 25,436 Blank = No sixth related stay 406-407 Facility Number 25,436 Blank = No sixth related stay 408-409 Stay Number Within Facility 25,436 Blank = No sixth related stay (410-414) ID of Seventh Related Stay 410 Survey Period Identifier 25,436 Blank = No seventh related stay 411-412 Facility Number 25,436 Blank = No seventh related stay 413-414 Stay Number Within Facility 25,436 Blank = No seventh related stay (415-419) ID of Eighth Related Stay 415 Survey Period Identifier 25,436 Blank = No eighth related stay 419-417 Facility Number 25,436 Blank = No eighth related stay 418-419 Stay Number Within Facility 25,436 Blank = No eighth related stay (420-424) ID of Ninth Related Stay 420 Survey Period Identifier 25,436 Blank = No ninth related stay 421-422 Facility Number 25,436 Blank = No ninth related stay 423-424 Stay Number Within Facility 25,436 Blank = No ninth related stay (425-429) ID of Tenth Related Stay 425 Survey Period Identifier 25,436 Blank = No tenth related stay 426-427 Facility Number 25,436 Blank = No tenth related stay 428-429 Stay Number Within Facility 25,436 Blank = No tenth related stay Figure 1 Health Care Facility Record Layout Figure 1 NHANES I Epidemiologic Followup Study (NHEFS) Health care facility record layout Facility identifiers . Actual dates . Codes assigned by Reported date of Match admission and NCHS to identify admission or discharge stays contained Reported cause of reason for . ICD-9-CM diagnoses within other stays admission non-match . Discharge status Source of report from hospitals and nursing homes Record Related Report Section Status Section Abstract Section Stay section Figure 2 Examples of Matching Process and Record Status Codes Figure 2 NHANES I Epidemiologic Followup Study (NHEFS) Examples of matching process and record status codes Record status code Match Report Section Mat Abstract Section non- Non-match Report Section match No Abstract code received Additional abstract No report ASF Abstract Section found section APPENDIX A 1982-84 RECORD STATUS CODES Code Frequency Description ANO- 268 "Authorization Not Obtained." This code indicates that the subject or proxy refused to sign the Medical Authori- zation Form (MAF). Information on these stays were not requested from the reported facilities. ASF- 5668 "Additional Stay Found." This code was assigned when a returned in-scope abstract could not be matched to a reported stay. This code was also assigned to in-scope abstracts that were received as a result of an inquiry generated by a type D report (Position 199). The type D report was deleted from the final file. FNC- 407 "Facility Never Contacted." This code was assigned when the facility was not contacted for the following reasons: the respondent could not recall the name of the facility; the facility was closed; the facility could not be lo- cated; and facility was located outside the United States. MAT- 12,835 "Record Match." This code was assigned when a received abstract matched a reported stay. This code was assigned to in-scope and type C (position 199) reports, but never to type D reports. In-scope abstracts that were received as the result of a type D report were assigned an ASF code. (See ASF.) ONR- 1196 "Other Non-Response." This code was assigned to a stay when no response for the stay request had been received from the facility by the end of the study period. REF- 184 "Refused." This code was assigned if a facility refused to send back the abstract requested. It is record, not subject specific. For example, a facility may have sent some abstracts for a subject but refused to send others. XNH- 587 "Subject Never at Facility." This code was used when the facility indicated that the patient was never admitted to that facility. XNS- 4194 "Other - No Stay Found." This code was assigned when a facility responded it was unable to send abstracts because no in-scope stay was found at the facility, or when the facility returned the request form without abstracts and provided no explanation for the failure to do so. Code Frequency Description XRD- 97 "Record Destroyed or No Longer Available." This code was assigned if the facility attempted to locate the abstract but stated that it no longer existed, i.e., was destroyed, or lost. NOTE: Additional information concerning the assignment of the record status codes is found in the introduction to this section. APPENDIX B 1982-84 Codes for Health Care Facility Stay Records NUMERIC CODES FOR REPORTED CONDITIONS ON HEALTH CARE FACILITY STAY RECORDS Code for reported Condition Condition Description 01 Arthritis 02 Gout 03 Heart attack 04 Another heart condition besides heart attack 05 Coronary bypass surgery 06 Pacemaker repair, insertion and/or replacement 07 T.I.A. small stroke 08 Stroke or CVA (cerebrovascular accident) 09 Diabetes 10 High blood pressure 11 Cancer and/or cancer treatment 12 Fractured hip 13 Another type of bone fracture besides a hip fracture 14 Pneumonia or influenza 15 Surgery 16 Don't know 17 Not ascertained 18 Tests/observation/x-rays/physical exam Code for reported Condition Condition Description 19 Digestive/endocrine condition 1901 Colon condition 1902 Ulcers 1903 Liver condition 1904 Colitis or enteritis 1905 Diverticulitis 1907 Gallbladder disease 20 Respiratory condition (other than influenza and pneumonia) 2001 Asthma 2002 Chronic bronchitis or emphysema 21 Infection 22 Kidney/bladder/urinary condition 23 Debility/pain 2301 Headache 24 Male reproductive condition 25 Musculoskeletal problem or injury other than a fracture 2501 Neck pain 2502 Back pain 2503 Hip pain 2504 Dislocated hip 2505 Other joint pain 26 Circulatory condition 27 Female reproductive condition 28 Mental illness 2801 Nervous breakdown 29 Neurologic condition 2901 Parkinson's disease 2902 Multiple sclerosis 2903 Epilepsy 30 Nutritional condition or dehydration 31 Bleeding or blood disorder 32 Skin condition 33 Condition not elsewhere coded Code for reported Condition Condition Description 34 Admission to a facility other than an acute care hospital 35 In a facility at time of death 36 Cataracts 3601 Glaucoma 3602 Detached retina 3603 Eye problem other than cataracts, detached retina or glaucoma 37 A fall Background During the process of completing the Hospital and Health Care Facility (HHCF) chart respondents were asked to describe the conditions that led to their facility stays and this information is included as a text field on the stay record. The text portion of the reported condition contains standard nomenclature words. If necessary the respondent's description was edited to fit into the 30 positions available in the record. A numeric code was also assigned to each description. This was done so that users would not have to deal with alphabetic description fields when investigating reasons for facility stays. Space is allotted on the report section of the facility stay record for recording of up to four reasons for the hospitalization or nursing home stay (positions 63-198 of the HCFS record). Note that code 1906 is not included in the coding structure for the 1982-84 file. This code had been designated for reports of overnight hospi- tal stays for thyroid disease. No such stays were reported. Reported conditions and their associated codes can be divided into six types depending on where in the interview the was reported and the amount of information obtained: specific conditions included in either the subject or proxy interview (Type A); conditions which are well-defined but for which no question exists in the interview (Type B); unknown conditions (Type C); conditions about which there is no specific question in the interview but for which sufficient information is available to attribute them to disorders of a major body system (Type D); conditions that are broadly defined and/or cannot be attributed to a single major body system (Type E); and conditions that cannot be classified into any of the above categories (Type F). Each condition type, the associated codes and the rules for assigning the reported conditions to the categories of the coding structure are described in detail below. Type A - Conditions about which the respondent was asked in the interview. For example, if a respondent answered "yes" to question G-26 ("Since 1970, had (he/she) ever stayed overnight in a hospital for arthritis?"), then a condition code of "01" and a test field containing "arthritis" would be included on the facility stay record. Type A conditions are listed below with the corresponding interview question number in parentheses. Unless otherwise indicated, the question is found in both the subject and proxy questionnaires. 01 Arthritis (G-26 of the proxy questionnaire) 03 Heart attack (G-17) 04 Other heart conditions (G-15 and G-16) 07 T.I.A., small stroke (G-21) 08 Stroke (G-22) 09 Diabetes (G-40 on the subject questionnaire and D-22 on the proxy questionnaire) 10 High blood pressure (D-5) 11 Cancer (D-65 and D-54 on the subject questionnaire and D-22 on the proxy questionnaire) 12 Fractured hip (E-94 on the subject questionnaire) 1901 Colon problem (G-8) 1902 Ulcers (G-5) 1903 Cirrhosis of the liver (G-9) 1904 Colitis or enteritis (G-14) 1905 Diverticulitis (G-19) 1907 Gallbladder disease (D-47 on the subject questionnaire and D-14 on the proxy questionnaire) 2001 Asthma (G-1) 2002 Chronic bronchitis and emphysema (G-2) 22 Kidney, bladder or urinary problem (G-6 and G-7) 2301 Headache (G-3) 2501 Neck pain (E-26 on the subject questionnaire) 2502 Back pain (E-46 on the subject questionnaire) 2503 Hip pain (E-59 on the subject questionnaire) 2504 Dislocated hip (E-99 on the subject questionnaire) 2505 Other joint problem (E-99 on the subject questionnaire) 2801 Nervous breakdown (G-12) 2901 Parkinson's disease (G-10) 2902 Multiple sclerosis (G-11) 2903 Epilepsy (G-50 on the subject questionnaire G-25 on the proxy questionnaire) 34 Care in non-acute care facility (G-62 on the subject question- naire and G-31 on the proxy questionnaire) 35 In a facility at death (V-3 on the proxy questionnaire) 36 Cataracts (G-18) 3601 Glaucoma (G-19) 3602 Detached retina (G-20) Complete agreement between responses to the questions in the interview and Type A condition codes on the facility stay file should not be expected. There are several reasons for a lack of agreement between these two data sources. First, the respondent may report a facility stay for a given condition in the interview and yet no facility stay record containing the condition may appear on the NCFS file. This would result if: (1) it was determined that the hospitalization did not last overnight causing the stay to be deleted from the HCFS file; or (2) the reported stay was found to be "out-of-scope". (See the introduction to this codebook and the Plan and Operation for defini- tions of out-of-scope stays.) Second, data may be inconsistent between the interview and the HCFS file of the respondent remembered and reported a condition after responding to the corresponding question in the interview. This tended to occur at the time the interviewer was recording information on the HHCF chart. For ex- ample, while recording information on a stay for high blood pressure, the respondent may add that he/she was also hospitalized at that time for a heart condition. The respondent may not have reported the hospitalization when asked about heart conditions in question G-15 and the Section G information may not have been updated to reflect this additional condition. However, heart condition would appear on the HCFS file. Type B - Conditions which do not have a corresponding question in the interview but for which sufficient descriptive information is available to allow them to be easily coded: 02 Gout 05 Coronary bypass surgery 06 Procedures for pacemakers 13 Bone fracture 14 Pneumonia and influenza 18 Test and observation 37 A fall Type C - Unknown conditions: 16 Don't know 17 Not ascertained Type D - Conditions for which there is not a specific question in the interview but which can be attributed to disorders of a major body system: 19 A condition of the digestive/endocrine system not found in the detailed conditions of the 1990 series codes (see Type A) 20 Respiratory conditions other than pneumonia, influenza, chronic bronchitis, emphysema or asthma 24 The male reproductive system 25 A condition of the musculoskeletal system not found in the detailed conditions of the 2500 series codes (see Type A) 26 The circulatory system (except strokes) 27 The female reproductive system 29 A neurologic disorder not found in the detailed conditions of the 2900 series codes (see Type A) 31 Blood disorders and bleeding 32 Skin problem 3603 Eye problem other than cataracts, detached retina or glaucoma Type E - Conditions which are broadly defined or are attributed to problems of more than one major body system: 15 Surgery 21 Infections 23 Debility and pain other than headache 28 Mental illness other than nervous breakdown 30 Nutrition and dehydration Type F - All conditions that cannot be assigned to one of the above codes: 33 Other conditions Additional information on reasons for a facility stay is available in the abstract section of the record (positions 205-379) if an abstract has been matched to the report. In general, information from the abstract is considered a more accurate determination of the conditions associated with the stay than are the reported conditions. The condition codes in the report section of stay records do provide useful information in the absence of a medical abstract. Both flexibility and caution should be exercised when selecting stays based on these codes. In order to help the analyst use these condition codes effectively, a description of the code assignment procedure along with an example is provided. Rules for Assignment The numeric codes were assigned to the respondent's non-technical descriptions by trained medical coders. In order to minimize variation among the coders assigning these codes, precedence rules were defined. Generally, a condition was coded to the most specific category in which it could be placed. The assignment rules are described below in primary order, e.g. Rule 2 was used only if Rule 1 did not apply and so forth. Rule 1: If a condition was one about which there was a specific question in either the subject or proxy interview, the code appropriate for that question was assigned. (Type A conditions) Rule 2: If the textual description could be coded to a narrowly defined condition not referenced in the interview or to the unknown category, the appropriate Type B or Type C code was assigned. Rule 3: Conditions that could not be coded to a specific question but could be coded to a major body system were assigned the appropriate Type D code. Rule 4: General descriptions, symptoms and conditions not coded by rules 1 through 3 were coded at the discretion of the medical coders, again with emphasis on as much specificity as possible. For example, "PAIN IN THE KNEES" would be coded to "25 - Debility and pain". (Type D or Type E conditions) Rule 5: Everything that could not be assigned a code after applying the above rules was coded to "33 - Other conditions". (Type F conditions) Considerations for the Data User These precedence rules were used for all three followups. However, since the questionnaires used in each followup differed slightly, the assignment of codes also differed. Questions about specific conditions were not always included in all three questionnaires. For example, Question B-63 in the 1986 interview asked about overnight stays for surgery making condi- tion code "15-Surgery" a Type A condition in the 1986 followup. There is no similar question in the 1982-84 or 1987 interview, therefore, surgery is a Type E condition in the 1982-84 and the 1987 files. In other cases, groups of conditions are combined into one question on one questionnaire but asked separately on another. For example, T.I.A.'s and other strokes are combined in one question in 1987. Since it was not possible to separate reports of T.I.A.'s from other strokes in the 1987 file, there are no conditions assign- ed to codes "07" in this file. There are reports assigned to "07" in the 1982-84 and 1986 files since separate T.I.A. and stroke questions were asked. An attempt was made to include as much detail in the code as possible. The questionnaire in the 1982-84 followup included enough detail to separate specific digestive conditions, such as colitis and gallbladder problems, from the general category of digestive disorders. Therefore, the 1982-84 HCFS data file, includes sub-codes under "19 - Digestive/endocrine system". Thus, analysts interested in colitis can identify cases from the reported condition section of the 1982-84 file but not from the 1986 or 1987 files. However, all files can be used to identify cases of the digestive/endocrine system in general. The analyst should refer to the questionnaire and the condition coding structure in the HCFS data tape codebook for the period of interest in order to obtain the maximal amount of information available. In using the condition codes to select records of interest, two characteristics of the coding structure should be considered: (1) the condition of interest may be found under more than one numeric code and (2) each numeric code covers more than one condition. To illustrate the first situation, consider a search for all reported stays with breast biopsies. A respondent might report a breast biopsy in response to the question relating to cancer and cancer treatment. In this case the textual field would contain a description such as "BIOPSY OF RIGHT BREAST" and the numeric code assigned would be 11 (indicating a response to the cancer stay question). Breast biopsies could also be reported in re- sponse to the surgery question in the 1986 followup and be assigned the code of 15. If the biopsy was reported in response to question G-61 on the 1982-84 questionnaire, "Have you stayed in a hospital for any other reason...?", it would be assigned to code 18 - Tests and observation". To identify breast biopsy cases it would be necessary to search the alphabetic fields for codes 11, 15 and 18. In addition, the reports of breast biopsies include several wording variations, for example, "BREAST BIOPSY", "BIOPSY OF BREAST". The analysts needs to investigate all possible wordings. To illustrate the second situation, consider code 18 - "Tests and observation". Over 250 different verbal descriptions have been coded to this category including a variety of radiological procedures, surgeries and physical examinations. Selecting just on code 18 will result in a wide variety of procedures. Those of a specific interest need to be identified by the textual description. Analysts who wish to use these reports, should print and review all the reported condition codes and alphabetic descriptions from the Health Care Facility Stay data files. Such a review will aid in (1) finding all the numeric condition codes under which the condition of interest will be found and (2) insuring that, within any numeric condition code, only the reports of interest will be selected. Finally, the condition codes in the report section should be used in conjunction with the information in the abstract section if it is available. Returned abstracts were matched to reports if one of the reported conditions matched one of the discharge diagnoses on the abstract. Other conditions reported for the same stay may or may not be confirmed in the matched medical abstract. If the condition of interest is not indicated as a discharge diagnosis on the medical record, the analyst may not want to accept the reported condition as a reason for the stay. Similarly, conditions may be listed as discharge diagnoses that do not appear on the report section. See the introduction to this codebook for a description of the match criteria.
