Public Health Briefs
Impact of HIV Infection on Mortality and Accuracy of AIDS Reporting on Death Certificates Nancy A. Hessol, MSPH, Susan P. Buchbinder, MD, David Colbert, Susan Scheer, MA, Ronald Underwood, MD, MPH, J. Lowell Barnhart, Paul M. O'Mally, Lynda S. Doll, PhD, and Alan R. Lifson, MD, MPH
Introduction To monitor the impact of specific diseases on mortality in the United States, accurate death certificate information is essential. Such accuracy is important for precise monitoring of mortality trends from acquired immunodeficiency syndrome (AIDS) and possible identification of unrecognized conditions associated with human immunodeficiency virus (HIV) infection. Recently, several US studies, using information from death certificates, have examined the impact of HIV infection and AIDS on mortality.'-5 These studies are limited by lack of specific risk-group information. Additionally, few studies have been able to assess the accuracy of AIDS reporting on death certificates5'6 because it is difficult to link US AIDS surveillance and vital statistics registries. In this analysis, we obtained information on HIV infection, reported AIDS diagnosis, and deaths among a San Francisco cohort of homosexual and bisexual men. Our objectives were to describe underlying causes of death; to assess underreporting of AIDS on death certificates; and to calculate cause-specific proportionate mortality ratios (PMRs), years of potential life lost (YPLL), and standardized mortality ratios (SMRs) for deceased cohort members.
Methods The San Francisco City Clinic cohort consists of 6704 homosexual and bisexual men recruited between 1978 and 1980 from the municipal sexually transmitted disease clinic for studies of hepatitis B.7-8 In 1980, hepatitis B vaccine trials began. Unused serum samples from these studies
were frozen and stored. In 1983 we began AIDS follow-up studies in this cohort. All participants reported to have AIDS were considered HIV antibody positive prior to death. For men who died of causes other than AIDS, stored specimens were tested for HIV antibody. To identify AIDS cases in the cohort, we cross-matched with San Francisco and national AIDS surveillance registries. To identify deaths among cohort members, we gathered information from San Francisco and national AIDS surveillance registries, newspaper obituaries, San Francisco Vital Statistics, and the National Death Index. Death certificates were obtained from San Francisco Vital Statistics and state registrars. All causes of death and other significant conditions were coded according to the current International Classification of Diseases ninth revision coding manual (ICD-9 CM).9 According to this system, underlying causes of death are assigned AIDS-related codes only when HIV infection or AIDS is noted. For this analysis, underlying cause of death Nancy A. Hessol, Susan P. Buchbinder, David Colbert, Susan Scheer, Ronald Underwood, J. Lowell Barnhart, Paul M. O'Malley, and Alan R. Lifson are with the AIDS Office, San Francisco Department of Public Health, San Francisco, Calif. Alan R. Lifson is also with the Department of Epidemiology and Biostatistics, School of Medicine, University of California, San Francisco, Calif. Lynda S. Doll is with the Division of HIV/AIDS, Center for Infectious Diseases, Centers for Disease Control, Atlanta, Ga. Requests for reprints should be sent to Nancy A. Hessol, MSPH, AIDS Office, 25 Van Ness Ave, Suite 500, San Francisco, CA 94102. This paper was submitted to the Journal April 25, 1991, and accepted with revisions August 23, 1991.
American Journal of Public Health 561
Pubic Health Briefs
each deceased cohort member was calculated by subtracting the age at death from 65 years. Summing the YPLL of all decedents dying of a particular cause gives the cause-specific YPLL. For the years 1981 and 1987, age-adjusted cause-specific death rates within the cohort were compared with United States data,1" and SMRs were used to measure the ratio of the observed number of deaths to the expected number of deaths.
Resudt
was determined according to the National Center for Health Statistics guidelines.10 Cause-specific PMRs were calculated as the number of deaths from a par-
562 American Journal of Public Health
ticular cause divided by the total number of deaths in the cohort. To evaluate temporal trends, cause-specific PMRs were calculated by year of death. The YPLL for
Through 1990, 1518 deaths had been reported in the cohort and 1292 death certificates obtained. The median year of death was 1987 (range 1978-1990) and the median age at death was 37 years (range 22-76). The racial/ethnic distribution was 92% White, 4% Latino, 3% African American, and 1% other, similar to the distribution of the cohort as a whole.7,8 Death certificates were obtained from 39 US states and territories. The majority, 1097 death certificates, came from California, including 919 from San Francisco. The most common underlying cause of death was HIV infection (Table 1). Of the 1292 decedents, 1194 were HIV antibody positive prior to death, 85 were HIV negative at their last blood test, and 13 had no previous HIV antibody results. The percentage of men who were HIV-positive prior to death was highest among those who died of infectious or parasitic diseases and lowest among thosewho died of liver disease, suicide, or injuries. Among the 1162 death certificates obtained for men who had previously been reported to AIDS surveillance, 1053 (91%) had HIV or AIDS noted. The most common underlying causes of death in the remaining 9% were neoplasms, immunodeficiency, and infectious and parasitic diseases (Table 2). Among the 1063 decedents with HIV or AIDS noted on the death certificate, only 7 had not been previously reported to AIDS surveillance. The PMRs for the five most common causes of death are shown in Table 3. The PMR was 84.6% for HIV infection, 3.4% for suicide, and less than 3% for all other causes. Over time, the PMR for HIV infection increased from 0% in 1978-1981 to 14% in 1982, 62% in 1984, 82% in 1986, 88% in 1988, and 93% in 1990. The cause-specific YPLLwas 29 123 for men with HIV or AIDS mentioned on the death certificate, 1251 for suicide, 980 for malignant neoplasms, and less than 900 for all other causes (Table 3). The total YPLL for all AIDS-related deaths, includ-
Aprd 1992, Vol. 82, No. 4
Public Health Brief
ing deaths occurring in men identified either through AIDS surveillance or AIDS on the death certificate, was 32 008. Age-adjusted cause-specific SMRs for the year 1981 show excess mortality for HIV infection and immune disorders (Table 4). SMRs for 1987 reveal a higher than expected rate for HIV infection and immune disorders and for suicide.
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M.M.
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Diwussion In the 1986-1987 US population, injuries and heart disease were the most common underlying causes of death among whitemenaged25 to44.11 Ourfindingsfrom the San Francisco City Clinic cohort show a different pattern, with AIDS as the leading underlying cause of death and YPLL. The underlying causesof death in our cohort are, however, simflar to those of the 1986-1987 San Francisco population for white men aged 25 to 44.11 Unlike mortality studies of HIV infection in intravenous drug users,4 most underlying causes of death associated with FHV infection in this cohort met the AIDS case definition. For example, sepsis was reported to be a common cause of death in intravenous drug userswho did not have AIDS,4 but in our study sepsis was usually reported with AIDS. Excess rates of suicide, however, warrant further investigation. AIDS surveillance provided more complete AIDS reporting than did death certificates, with 0.7% versus 9% underreporting. This low rate of underreporting (0.7%) is likely due to comprehensive case surveillance in San Francisco, which includes death certificate review for case identification. Even in a San Francisco cohort of homosexual and bisexual men, AIDS is underreported as an underlying cause of death on death certificates. The omission of HIV infection or AIDS on the death certificates may be due to lack of knowledge about proper completion of death certificates, intentional cover-ups to protect patients' confidentiality, cause of death's being unrelated to HIV infection, or incomplete knowledge of the decedent's medical condition. The impact of HIV infection and AIDS on premature mortality will continue to increase both in the cohort and in the United States. Because homosexual and bisexual men were among the first risk groups infected with HIV,7 the patterns seen in the San Francisco City Clinic cohort may predict future patterns for the United States. National mortality trends have already changed, with H1V infection
April 1992, Vol. 82, No. 4
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ranked sixth in 1989 for estimated YPLL among all persons dying before age 65.12 In 1988, HIV infection/AIDS became the third leading cause of death among US men 25 to 44 years of age; itwas estimated to be the second leading cause of death in 1989.13 As HIV infection spreads into other transmission risk groups, such as intravenous drug users, their sex partners, and their children, AIDS and HIV infection will continue to be an important cause of morbidity and premature mortality in the United States. [
Acknowledgments This study was supported by cooperative agreement number U64/CCU900523-06 from the Centers for Disease Control, Atlanta, Ga. Preliminary findings of this study were presented at the 118th meeting of the American Public Health Association in New York City on October 2, 1990. We thank the folowing people for their assistance in this study Torsten Bodecker, Lois Conley, Lyn Fischer-Ponce, Aida Flandez, Delia Garcia, Sandra Hernandez, Scott Holmberg, Fred Ingram, Mitchell Katz, Robert Kono, Irene Lee, Bobby Martin, Marvin Montenegro, Frank Phillips, Michael Piccii, Martha Rogers, Chris Rubino, George Rutherford, Belinda Van, Robert Wade, Katie Young, and the men in the San Francisco City Clinic cohort study.
References 1. Buehler JW, Devine OJ, Berkehnan RL, Chevarley FM. Impact of the human immunodeficiency virus epidemic on mortality trends inyoungmen, United States.Am JPublic Health. 1990;80:1080-1086. 2. Saunders LD, Rutherford GW, Lemp GF, Barnhart JL. Impact of AIDS on mortality in San Francisco, 1979-1986.JAID Syndr.
1990;3:921-924. 3. Menendez BS, Drucker E, Vermund SH, et al. AIDS mortality among Puerto Ricans and other Hispanics in New York City, 1981-1987. JAID Syndr. 1990;3:644-648. 4. Selwyn PA, Hartel D, Wasserman W, Drucker E. Impact of the AIDS epidemic on morbidity and mortality among intravenous drug users in a New York City methadone maintenance program. Am JPublic Health. 1989;79:1358-1362. 5. Kristal AR. The impact of the acquired immunodeficiency syndrome on patterns of premature death in NewYorkCity.JAMA 1986;255:2306-2310. 6. McCormick A. Trends in mortality statistics in England and Wales with particular reference to AIDS from 1984 to April 1987. Br Med J. 1988;296:1289-1292. 7. Hessol NA, Lifson AR, O'MalleyPM, Doll LS, Jaffe HW, Rutherford GW. Prevalence, incidence, and progression of human immunodeficiencmy virus infection in homosexual and bisexual men in hepatitis B vaccine trials, 1978-1988. Am J EpidemioL
1989;130:1167-1175.
American Journal of Public Health 563
Public Health Briefs
8. Rutherford GW, LifsonAR, Hessol NA, et al. Course of HIV-1 infection in a cohort of homosexual and bisexual men: an 11-year follow-up study. BrMedJ. 1990;301:11831188. 9. Intemational Classification of Diseases. 9th revision. Washington, DC: US Govemnment Printing Office; 1989. Clinical modification, DHHS publication PHS-891260. 10. National Center for Health Statistics. In-
~-
Robert A. Hiat, MD, PhD, Frank J. Capel, and Michael S. Ascher, MD
v:X'
Inrtdudion
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.......
......
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:
12. CentersforDisease Control. Update: years of potential life lost before age 65-United States, 1988 and 1989. MMWR 1991;40: 60-63. 13. Centers for Disease Control. Mortality attnbutable to HIV infection/AIDS-United States, 1981-1990. MMIWR 1991;40:41-44. 14. Gardner MJ, Altman DG. Statistics with Confidene. London: British Medical Journal; 1989:59.
Seroprevalence of HIV-Type 1 in a Northern California Health Plan Population: An Unlinked Survey
v~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~U.
_
stnction Manual Part 2a.- Instrncions for casfying the udring cause of death 1990. Hyattsvflle, Md: US Dept of Health and Human Services, Public Health Service; 1990. 11. National Center for Health Statstics. CornpnsdMotaly, 1979-1987. National Vital Statistics System. Hyattsville, Md: US Dept of Health and Human Services, Public Health Service, Centers for Disease Control; 1990.
......'°
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_ X~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~- - .......
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'"
Seroprevalence studies designed to assess the spread of human immunodeficiency virus-type 1 (HIV-1) infection in the general population are usually biased by the selected or voluntary nature of the sample or are limited in their generalizability because of the specialized nature of the survey population.1-5 Unlinked (blinded) surveys bypass the need for informed consent and thus eliminate selection bias from this source. We conducted an unlinked survey among nonhospitalized members of a large northern California prepaid health plan with characteristics representative of the general population in that region. The study protocol was approved by the Institutional Review Board of the Kaiser Permanente Medical Care Program (KPMCP), Northern California Region. We believe our results can be generalized to the symptom-free general population surrounding the city of San Francisco, one of the areas with the highest prevalence of HIV-1 in the United States.
Methis Stdy Population The KPMCP is a group-model, prepaid health maintenance organization that in 1989 provided comprehensive medical care to 2 190 629 members, or approximately 30%0 of the population in the counties of northern California where KPMCP provides services. The membership is comparable with the general population in
terms of age and sex, and it includes the full spectrum of the region's racial, occupational, and socioeconomic groups.6,7
Data Collection At most KPMCP facilities, members older than 15 years of age can voluntarily take a personal health appraisal (PHA) that includes a questionnaire, a physical examination, and laboratory tests. A PHA might be done because of a member's or provider's perceived need for a checkup, either to collect baseline data when the member first joins the health plan or starts with the new provider, or to provide a broadly based assessment for nonspecific complaints or concerns. It is generally not used as a diagnostic tool for focused complaints. Persons who take PHAs are likely to differ from the general plan membership; however, except in one facility,7 this trend has not been systematically examined. Aliquots of sera from 10 000 consecutive PHA samples drawn at nine Kaiser Foundation facilities (Figure 1) in October Robert A. Hiatt is with the Division of Research, Kaiser Permanente Medical Care Program. Frank J. Capell is with the Office of AIDS and Michael S. Ascher is with the Viral and Rickettsial Disease Laboratory of the California Department of Health Services. Requests for reprints should be sent to Robert A. Hiatt, MD, PhD, Division of Research, Kaiser Permanente Medical Care Program, 3451 Piedmont Avenue, Oakland, CA 94611-5463. This paper was submitted to the Journal April 17, 1991, and acceptedwith revisions September 20, 1991.
April 1992, Vol. 82, No. 4
Impact of HIV Infection on Mortality and Accuracy of AIDS Reporting on Death Certificates Nancy A. Hessol, MSPH, Susan P. Buchbinder, MD, David Colbert, Susan Scheer, MA, Ronald Underwood, MD, MPH, J. Lowell Barnhart, Paul M. O'Mally, Lynda S. Doll, PhD, and Alan R. Lifson, MD, MPH
Introduction To monitor the impact of specific diseases on mortality in the United States, accurate death certificate information is essential. Such accuracy is important for precise monitoring of mortality trends from acquired immunodeficiency syndrome (AIDS) and possible identification of unrecognized conditions associated with human immunodeficiency virus (HIV) infection. Recently, several US studies, using information from death certificates, have examined the impact of HIV infection and AIDS on mortality.'-5 These studies are limited by lack of specific risk-group information. Additionally, few studies have been able to assess the accuracy of AIDS reporting on death certificates5'6 because it is difficult to link US AIDS surveillance and vital statistics registries. In this analysis, we obtained information on HIV infection, reported AIDS diagnosis, and deaths among a San Francisco cohort of homosexual and bisexual men. Our objectives were to describe underlying causes of death; to assess underreporting of AIDS on death certificates; and to calculate cause-specific proportionate mortality ratios (PMRs), years of potential life lost (YPLL), and standardized mortality ratios (SMRs) for deceased cohort members.
Methods The San Francisco City Clinic cohort consists of 6704 homosexual and bisexual men recruited between 1978 and 1980 from the municipal sexually transmitted disease clinic for studies of hepatitis B.7-8 In 1980, hepatitis B vaccine trials began. Unused serum samples from these studies
were frozen and stored. In 1983 we began AIDS follow-up studies in this cohort. All participants reported to have AIDS were considered HIV antibody positive prior to death. For men who died of causes other than AIDS, stored specimens were tested for HIV antibody. To identify AIDS cases in the cohort, we cross-matched with San Francisco and national AIDS surveillance registries. To identify deaths among cohort members, we gathered information from San Francisco and national AIDS surveillance registries, newspaper obituaries, San Francisco Vital Statistics, and the National Death Index. Death certificates were obtained from San Francisco Vital Statistics and state registrars. All causes of death and other significant conditions were coded according to the current International Classification of Diseases ninth revision coding manual (ICD-9 CM).9 According to this system, underlying causes of death are assigned AIDS-related codes only when HIV infection or AIDS is noted. For this analysis, underlying cause of death Nancy A. Hessol, Susan P. Buchbinder, David Colbert, Susan Scheer, Ronald Underwood, J. Lowell Barnhart, Paul M. O'Malley, and Alan R. Lifson are with the AIDS Office, San Francisco Department of Public Health, San Francisco, Calif. Alan R. Lifson is also with the Department of Epidemiology and Biostatistics, School of Medicine, University of California, San Francisco, Calif. Lynda S. Doll is with the Division of HIV/AIDS, Center for Infectious Diseases, Centers for Disease Control, Atlanta, Ga. Requests for reprints should be sent to Nancy A. Hessol, MSPH, AIDS Office, 25 Van Ness Ave, Suite 500, San Francisco, CA 94102. This paper was submitted to the Journal April 25, 1991, and accepted with revisions August 23, 1991.
American Journal of Public Health 561
Pubic Health Briefs
each deceased cohort member was calculated by subtracting the age at death from 65 years. Summing the YPLL of all decedents dying of a particular cause gives the cause-specific YPLL. For the years 1981 and 1987, age-adjusted cause-specific death rates within the cohort were compared with United States data,1" and SMRs were used to measure the ratio of the observed number of deaths to the expected number of deaths.
Resudt
was determined according to the National Center for Health Statistics guidelines.10 Cause-specific PMRs were calculated as the number of deaths from a par-
562 American Journal of Public Health
ticular cause divided by the total number of deaths in the cohort. To evaluate temporal trends, cause-specific PMRs were calculated by year of death. The YPLL for
Through 1990, 1518 deaths had been reported in the cohort and 1292 death certificates obtained. The median year of death was 1987 (range 1978-1990) and the median age at death was 37 years (range 22-76). The racial/ethnic distribution was 92% White, 4% Latino, 3% African American, and 1% other, similar to the distribution of the cohort as a whole.7,8 Death certificates were obtained from 39 US states and territories. The majority, 1097 death certificates, came from California, including 919 from San Francisco. The most common underlying cause of death was HIV infection (Table 1). Of the 1292 decedents, 1194 were HIV antibody positive prior to death, 85 were HIV negative at their last blood test, and 13 had no previous HIV antibody results. The percentage of men who were HIV-positive prior to death was highest among those who died of infectious or parasitic diseases and lowest among thosewho died of liver disease, suicide, or injuries. Among the 1162 death certificates obtained for men who had previously been reported to AIDS surveillance, 1053 (91%) had HIV or AIDS noted. The most common underlying causes of death in the remaining 9% were neoplasms, immunodeficiency, and infectious and parasitic diseases (Table 2). Among the 1063 decedents with HIV or AIDS noted on the death certificate, only 7 had not been previously reported to AIDS surveillance. The PMRs for the five most common causes of death are shown in Table 3. The PMR was 84.6% for HIV infection, 3.4% for suicide, and less than 3% for all other causes. Over time, the PMR for HIV infection increased from 0% in 1978-1981 to 14% in 1982, 62% in 1984, 82% in 1986, 88% in 1988, and 93% in 1990. The cause-specific YPLLwas 29 123 for men with HIV or AIDS mentioned on the death certificate, 1251 for suicide, 980 for malignant neoplasms, and less than 900 for all other causes (Table 3). The total YPLL for all AIDS-related deaths, includ-
Aprd 1992, Vol. 82, No. 4
Public Health Brief
ing deaths occurring in men identified either through AIDS surveillance or AIDS on the death certificate, was 32 008. Age-adjusted cause-specific SMRs for the year 1981 show excess mortality for HIV infection and immune disorders (Table 4). SMRs for 1987 reveal a higher than expected rate for HIV infection and immune disorders and for suicide.
............ ...............
...
...........................
M.M.
....................
....
....... ........
Diwussion In the 1986-1987 US population, injuries and heart disease were the most common underlying causes of death among whitemenaged25 to44.11 Ourfindingsfrom the San Francisco City Clinic cohort show a different pattern, with AIDS as the leading underlying cause of death and YPLL. The underlying causesof death in our cohort are, however, simflar to those of the 1986-1987 San Francisco population for white men aged 25 to 44.11 Unlike mortality studies of HIV infection in intravenous drug users,4 most underlying causes of death associated with FHV infection in this cohort met the AIDS case definition. For example, sepsis was reported to be a common cause of death in intravenous drug userswho did not have AIDS,4 but in our study sepsis was usually reported with AIDS. Excess rates of suicide, however, warrant further investigation. AIDS surveillance provided more complete AIDS reporting than did death certificates, with 0.7% versus 9% underreporting. This low rate of underreporting (0.7%) is likely due to comprehensive case surveillance in San Francisco, which includes death certificate review for case identification. Even in a San Francisco cohort of homosexual and bisexual men, AIDS is underreported as an underlying cause of death on death certificates. The omission of HIV infection or AIDS on the death certificates may be due to lack of knowledge about proper completion of death certificates, intentional cover-ups to protect patients' confidentiality, cause of death's being unrelated to HIV infection, or incomplete knowledge of the decedent's medical condition. The impact of HIV infection and AIDS on premature mortality will continue to increase both in the cohort and in the United States. Because homosexual and bisexual men were among the first risk groups infected with HIV,7 the patterns seen in the San Francisco City Clinic cohort may predict future patterns for the United States. National mortality trends have already changed, with H1V infection
April 1992, Vol. 82, No. 4
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ranked sixth in 1989 for estimated YPLL among all persons dying before age 65.12 In 1988, HIV infection/AIDS became the third leading cause of death among US men 25 to 44 years of age; itwas estimated to be the second leading cause of death in 1989.13 As HIV infection spreads into other transmission risk groups, such as intravenous drug users, their sex partners, and their children, AIDS and HIV infection will continue to be an important cause of morbidity and premature mortality in the United States. [
Acknowledgments This study was supported by cooperative agreement number U64/CCU900523-06 from the Centers for Disease Control, Atlanta, Ga. Preliminary findings of this study were presented at the 118th meeting of the American Public Health Association in New York City on October 2, 1990. We thank the folowing people for their assistance in this study Torsten Bodecker, Lois Conley, Lyn Fischer-Ponce, Aida Flandez, Delia Garcia, Sandra Hernandez, Scott Holmberg, Fred Ingram, Mitchell Katz, Robert Kono, Irene Lee, Bobby Martin, Marvin Montenegro, Frank Phillips, Michael Piccii, Martha Rogers, Chris Rubino, George Rutherford, Belinda Van, Robert Wade, Katie Young, and the men in the San Francisco City Clinic cohort study.
References 1. Buehler JW, Devine OJ, Berkehnan RL, Chevarley FM. Impact of the human immunodeficiency virus epidemic on mortality trends inyoungmen, United States.Am JPublic Health. 1990;80:1080-1086. 2. Saunders LD, Rutherford GW, Lemp GF, Barnhart JL. Impact of AIDS on mortality in San Francisco, 1979-1986.JAID Syndr.
1990;3:921-924. 3. Menendez BS, Drucker E, Vermund SH, et al. AIDS mortality among Puerto Ricans and other Hispanics in New York City, 1981-1987. JAID Syndr. 1990;3:644-648. 4. Selwyn PA, Hartel D, Wasserman W, Drucker E. Impact of the AIDS epidemic on morbidity and mortality among intravenous drug users in a New York City methadone maintenance program. Am JPublic Health. 1989;79:1358-1362. 5. Kristal AR. The impact of the acquired immunodeficiency syndrome on patterns of premature death in NewYorkCity.JAMA 1986;255:2306-2310. 6. McCormick A. Trends in mortality statistics in England and Wales with particular reference to AIDS from 1984 to April 1987. Br Med J. 1988;296:1289-1292. 7. Hessol NA, Lifson AR, O'MalleyPM, Doll LS, Jaffe HW, Rutherford GW. Prevalence, incidence, and progression of human immunodeficiencmy virus infection in homosexual and bisexual men in hepatitis B vaccine trials, 1978-1988. Am J EpidemioL
1989;130:1167-1175.
American Journal of Public Health 563
Public Health Briefs
8. Rutherford GW, LifsonAR, Hessol NA, et al. Course of HIV-1 infection in a cohort of homosexual and bisexual men: an 11-year follow-up study. BrMedJ. 1990;301:11831188. 9. Intemational Classification of Diseases. 9th revision. Washington, DC: US Govemnment Printing Office; 1989. Clinical modification, DHHS publication PHS-891260. 10. National Center for Health Statistics. In-
~-
Robert A. Hiat, MD, PhD, Frank J. Capel, and Michael S. Ascher, MD
v:X'
Inrtdudion
-- ------------
'I~~
g
.......
......
-- ----
_~~ ~~~~~~~~~~~~~~~~~~~~~~~~... _ |
|eXs~~~~~~~~~~~~~~~~~~~~~.....
_x
............
OWN'
:
12. CentersforDisease Control. Update: years of potential life lost before age 65-United States, 1988 and 1989. MMWR 1991;40: 60-63. 13. Centers for Disease Control. Mortality attnbutable to HIV infection/AIDS-United States, 1981-1990. MMIWR 1991;40:41-44. 14. Gardner MJ, Altman DG. Statistics with Confidene. London: British Medical Journal; 1989:59.
Seroprevalence of HIV-Type 1 in a Northern California Health Plan Population: An Unlinked Survey
v~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~U.
_
stnction Manual Part 2a.- Instrncions for casfying the udring cause of death 1990. Hyattsvflle, Md: US Dept of Health and Human Services, Public Health Service; 1990. 11. National Center for Health Statstics. CornpnsdMotaly, 1979-1987. National Vital Statistics System. Hyattsville, Md: US Dept of Health and Human Services, Public Health Service, Centers for Disease Control; 1990.
......'°
X
_ X~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~- - .......
X:
C':X
'"
Seroprevalence studies designed to assess the spread of human immunodeficiency virus-type 1 (HIV-1) infection in the general population are usually biased by the selected or voluntary nature of the sample or are limited in their generalizability because of the specialized nature of the survey population.1-5 Unlinked (blinded) surveys bypass the need for informed consent and thus eliminate selection bias from this source. We conducted an unlinked survey among nonhospitalized members of a large northern California prepaid health plan with characteristics representative of the general population in that region. The study protocol was approved by the Institutional Review Board of the Kaiser Permanente Medical Care Program (KPMCP), Northern California Region. We believe our results can be generalized to the symptom-free general population surrounding the city of San Francisco, one of the areas with the highest prevalence of HIV-1 in the United States.
Methis Stdy Population The KPMCP is a group-model, prepaid health maintenance organization that in 1989 provided comprehensive medical care to 2 190 629 members, or approximately 30%0 of the population in the counties of northern California where KPMCP provides services. The membership is comparable with the general population in
terms of age and sex, and it includes the full spectrum of the region's racial, occupational, and socioeconomic groups.6,7
Data Collection At most KPMCP facilities, members older than 15 years of age can voluntarily take a personal health appraisal (PHA) that includes a questionnaire, a physical examination, and laboratory tests. A PHA might be done because of a member's or provider's perceived need for a checkup, either to collect baseline data when the member first joins the health plan or starts with the new provider, or to provide a broadly based assessment for nonspecific complaints or concerns. It is generally not used as a diagnostic tool for focused complaints. Persons who take PHAs are likely to differ from the general plan membership; however, except in one facility,7 this trend has not been systematically examined. Aliquots of sera from 10 000 consecutive PHA samples drawn at nine Kaiser Foundation facilities (Figure 1) in October Robert A. Hiatt is with the Division of Research, Kaiser Permanente Medical Care Program. Frank J. Capell is with the Office of AIDS and Michael S. Ascher is with the Viral and Rickettsial Disease Laboratory of the California Department of Health Services. Requests for reprints should be sent to Robert A. Hiatt, MD, PhD, Division of Research, Kaiser Permanente Medical Care Program, 3451 Piedmont Avenue, Oakland, CA 94611-5463. This paper was submitted to the Journal April 17, 1991, and acceptedwith revisions September 20, 1991.
April 1992, Vol. 82, No. 4
