Effectiveness of highly active antiretroviral therapy in Spanish cohorts of HIV seroconverters: differences by transmission category

Abstract

Objective: To evaluate the population effectiveness of highly active antiretroviral therapy (HAART) in HIV progression and determine the heterogeneity of the effect of HAART in GEMES (Spanish multicenter study of seroconverters).

Design: Multicenter cohort study.

Methods: Data from 1091 persons with well-documented HIV seroconversion dates from 1980s to January 2000 were analysed. Risk of AIDS and death in subjects with same duration of HIV infection were compared in different calendar periods; before 1992, 1992-1995 (reference), 1996-1997, 1998 and 1999 with Kaplan-Meier methods and Cox proportional hazards models, allowing for late entry, fitting calendar period as time-dependent covariate and adjusting for transmission category, age and gender.

Results: Statistically significant reductions in the risk of AIDS were first observed in 1998 [hazard ratio (HR), 0.59; 95% confidence interval (CI), 0.35-1.01] becoming more pronounced in 1999 (HR, 0.45; 95% CI, 0.24-0.84). Reduction in the risk of death was seen in 1997, though only reached borderline significance in 1999 (HR, 0.53; 95% CI, 0.26-1.07). Progression to AIDS and death was slower in women (HR, 0.68; 95% CI, 0.46-0.99 and HR, 0.53; 95% CI, 0.33-0.87, respectively). Compared with men who have sex with men (MSM), intravenous drug users (IDU) had lower reductions in the risk of AIDS and death.

Conclusions: Reductions in incidence of AIDS and death in GEMES are seen after 1998 and 1999, respectively, compared with 1992-1995, being more pronounced in MSM compared with IDU, the commonest category in Spain.