FACTORS ASSOCIATED WITH CHANGES IN THE USE OF ANTIRETROVIRAL THERAPY BY A COHORT OF HOMOSEXUAL MEN INFECTED WITH HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-I

Changes in the use of antiretroviral drugs and factors associated with changes from monotherapy with zidovudine (ZDV) to other regimens were quantified in the Multicenter AIDS Cohort Study, Participants who had been receiving monotherapy with ZDV were categorized as (1) discontin uing ZDV monotherapy; (2) switching to didanosine (ddI), zalcitabine ( ddC), or stavudine (d4T) monotherapy; (3) switching to combination the rapy (ZDV with ddI, ddC, or d4T); or (4) continuing ZDV monotherapy. F rom 1990 to 1994, the percentage of participants using ZDV monotherapy decreased from 27% to 17% (among participants without AIDS) and from 60% to 17% (among those with AIDS). At the same time, the proportion o f participants using combination therapy increased from zero to 11% (n o AIDS) and from 2% to 21% (AIDS), and the proportion switching to a d ifferent monotherapy increased from zero to 8% (no AIDS) and from 8% t o 26% (AIDS). Polychotomous logistic regression methods were used to i dentify the factors predicting changes from ZDV monotherapy. Among par ticipants without AIDS, indicators of drug failure (such as a lower CD 4 lymphocyte count or symptoms of human immunodeficiency virus type 1 infection) were predictive of the initiation of combination therapy, w hile among patients with AIDS they were predictive of a switch to an a lternative monotherapy. A decrease in hemoglobin levels, a marker of Z DV toxicity, was predictive for all patients of a switch to other mono therapy. In addition, private health insurance coverage was associated with reduced odds of the discontinuation of antiretroviral therapy. T hese data show that clinicians and patients are opting for more aggres sive antiretroviral regimens and that changes in CD4 lymphocyte count and in the status of symptoms remain the primary guides for changes in therapy.