Codes and Frequencies
HEPATYRC indicates whether the person had chronic hepatitis in the past year. This variable is created with supplemental programming by the IPUMS NHIS staff from the pre-1997 condition records. For general information about IHIS variables (such as HEPATYRC) created from the pre-1997 condition records, see the User Note on Condition Records and Condition Variables.
Defining Hepatitis Records and Identifying Persons with Hepatitis
For all available years, persons who were asked a direct question about hepatitis and who have a chronic hepatitis condition record are given a "Yes" code for HEPATYRC. Persons who were asked a direct question about hepatitis but do not have a chronic hepatitis record are given a code of "No." Persons who were not asked a direct question about hepatitis, or for whom it is unknown whether they were asked such a question, are given a code of "NIU" (not in universe), regardless of whether they have a chronic hepatitis record.
1975 and 1978
For 1975 and 1978, hepatitis records were defined as those condition records with a code of "175" ("Hepatitis, not otherwise specified") in the variable DIAGR1 in the original NHIS public use files. This condition code value comes from NCHS's Diagnostic Recode #1: Diseases, Injuries, and Impairments, not from the International Classification of Diseases (ICD) codes. Additionally, to be considered "chronic," hepatitis condition records must have a code of "1" ("Chronic") in the variable CACODE in the original NHIS public use files.
1979 to 1996
For 1979-1996, chronic hepatitis records were defined as those condition records with any of the following codes in the variable CDICDCOD in the original NHIS public use files:
- "5714" ("Chronic hepatitis")
- "5731" ("Hepatitis in viral diseases classified elsewhere")
- "5732" ("Hepatitis in other infectious diseases classified elsewhere")
- "5733" ("Hepatitis, unspecified")
These condition code values come from ICD Revision 9. As with earlier years, to be considered "chronic," hepatitis condition records must have a code of "1" ("Chronic") in the variable CACODE in the original NHIS public use files.
For 1975, HEPATYRC should be weighted with PERWEIGHT.
For 1978 to 1981, HEPATYRC should be weighted with CONDWT1.
For 1982 to 1996, HEPATYRC should be weighted with CONDWT3.
Related Hepatitis Variables
The nearest equivalent of HEPATYRC available for 1997 forward is HEPATEV (Ever had hepatitis). However, researchers should use caution when comparing prevalence estimates derived from these two variables, as both the manner of collecting information about hepatitis and the reference period differ greatly between the two. HEPATYRC was created by recoding condition records that were generated in response to several different survey questions about health problems underlying disability, sick days, or contacts with health care practitioners in the past year. HEPATEV, by contrast, is based on a direct question about whether the person ever had the condition hepatitis.
As with all of the person-level condition variables created by IHIS from condition records prior to 1997, the universe for HEPATYRC is substantially different for 1978 forward than it is for years prior to 1978. Beginning in 1978, only persons living in 1/6 of households, rather than all persons, were asked a direct question about having hepatitis in the past year. There is also a minor universe change between the sets of years 1978-1981 and 1982-1996. These changes require that different weight variables be used depending on which years of data are analyzed. See the "Description" tab for details.
Additionally, there is a change in the way "Yes" responses are coded over time. See the User Note on Condition Records and Condition Variables for details about the composite coding scheme employed by IHIS.
- 1975: All persons.
- 1978-1981: Persons living in 1/6 of households (who received Condition List 1).
- 1982-1996: Persons living in 1/6 of households (who received Condition List 3).
- 1975, 1978-1996