Determinants of clinical progression in antiretroviral-naive HIV-infected patients starting highly active antiretroviral therapy.: Aquitaine Cohort, France, 1996-2002

Objectives To determine the factors associated with clinical progression (AIDS events and death) in antiretroviral-naive patients who have begun highly active antiretroviral therapy (HAART). Methods HIV-infected patients naive to antiretroviral therapy were included in a prospective hospital-based cohort who began HAART between June 1996 and December 2001. Progression was explained by baseline characteristics using Cox proportional hazards models. Results Overall, data for 709 patients were analysed. In multivariate analysis, factors associated with an increased risk of progression were CD4 count < 50 cells/mu L [hazard ratio (HR) = 13.0 (95% confidence interval 3.8-44.3)] and between 50 and 199 cells/mu L [HR = 5.1 (1.6-16.3)], when compared with patients with CD4 count > 3 50 cells/mu L; AIDS events before HAART prescription [HR 2.1 (1.2-3.7)]; COB count < 400 cells/mu L [HR 1.8 (1.1-3.0)]; and older age (HR = 1.2 by 10 years (1.0-1.5)]. In a second model including CD4 percentage, factors associated with progression were CD4 < 10% [HR = 6.3 (2.2-17.9)] and 10% < CD4 < 15% [HR = 4.2 (1.4-12.5)], when compared with patients with CD4 > 20%; CD8 count; AIDS events before HAART prescription; and older age. In a third model including the CD4:CD8 ratio, factors associated with progression were CD4:CD8 < 15% [HR = 8.2 (2.3-28.8)] and 15% < CD4:CD8 < 30% [HR = 4.6 (1.3-16.0)], when compared with patients with CD4:CD8 > 45%; AIDS events before HAART prescription; and older age. The Akaike information criteria for model analysis were 803, 805 and 815, respectively. Conclusions Consideration of CD4 level in terms of CD4:CD8 ratio or CD4 percentage can be a good alternative to absolute CD4 count. Other prognostic factors such as older age, CD8 count < 400 cells/mu L and AIDS events also have to be considered in the decision to initiate HAART.