Seroprevalence of human immunodeficiency virus among family practice outpatients

Because the human immunodeficiency virus (HIV) is extremely heterogeneous in its impact on various subpopulations, it is important to carry out HIV seroprevalence studies in different subpopulations using standardized techniques. The present study is the first to report seroprevalence rates of HIV in family medicine outpatient populations.

To estimate the prevalence and demographic distribution of HIV, 3874 sera samples were collected anonymously at six family medicine clinics in San Bernardino County during a 1-year period.

Fifty-nine (1.52 percent) of the sera samples were confirmed HIV-positive. Of the 59 HIV-positive patients, 43 were visiting the clinic for HIV-related reasons. Excluding these 43 cases, and adjusting for age and race using the county population as a standard, the overall rate of HIV infection was 0.45 percent. The 16 HIV-positive patients who visited the clinics for reasons unrelated to HIV were between the ages of 20 and 59 years, with the 30- to 39-year-old age group having the highest prevalence (1.4 percent). Seroprevalence was eight times higher for men than women (chi 2 = 14.3, P = 0.0002), and rates for African-Americans (0.85 percent) were two to three times higher than for Hispanics (0.40 percent) and whites (0.25 percent).

Results of this study are consistent with and support findings from previous surveys of more general populations in the western United States. There are approximately 7800 HIV-infected persons residing in San Bernardino County, and an estimated $796 million will be required to treat these individuals.