LABORATORY MARKERS AND THE RISK OF DEVELOPING HIV-1 DISEASE AMONG INJECTING DRUG-USERS

Objective: To characterize the progression to HIV-1 disease among inje ction drug users (IDU) according to laboratory markers. D Design: Pros pective study of cohort of HIV-1-seroprevalent IDU, with case-comparis on component. Methods: Different laboratory markers were examined as p redictors of progression to HIV-1-associated diseases including AIDS i n a cohort of 318 HIV-1-infected IDU. The cohort was enrolled from a m ethadone treatment program in the Bronx, New York, USA. The independen t utility of non-CD4 cell markers was evaluated after adjustment for t he association of low CD4 lymphocyte count with AIDS risk. Clinical ev ents in the natural history of HIV-1 were related to changes in levels of two variables related to duration of infection, CD4 lymphocyte cou nt and serum beta(2)-microglobulin (beta(2)M) concentration. Results: On univariate analysis, AIDS incidence measured from baseline increase d with declining CD4 lymphocyte number and percentage, increasing seru m beta(2)M level, low platelet count, low leukocyte count and p24 anti genemia. Among HIV-1-related outcomes prior to any AIDS diagnosis, the relative risk of pyogenic bacterial infections conferred by these mar kers was similar to the relative risk of AIDs. For all HIV-1 outcomes, the elevated risk encountered at CD4 lymphocyte number less than or e qual to 200 x 10(6)/l was entirely due to the high risk at less than o r equal to 150 x 10(6)/l. On multivariate analysis, control for CD4 ly mphocyte count eliminated the association of any other marker with inc reased AIDS hazard. HIV-1-related outcomes tended to occur in this ord er: multiple constitutional symptoms, oral candidiasis, pyogenic bacte rial infections of AIDS. Conclusions: In HIV-1-infected IDU, several l aboratory markers may predict AIDS when analyzed individually. These a re not, however, independently related to increased AIDS risk after ad justment for low CD4 lymphocyte count. A CD4 count less than or equal to 150 x 10(6)/l is more strongly related to immediate risk of adverse outcome than a count of 200 x 10(6)/l. A progressive series of clinic al events is associated with markers of duration of HIV-1 infection, p rior to and including AIDS diagnosis.