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

Abstract

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/microL [hazard ratio (HR) = 13.0 (95% confidence interval 3.8-44.3)] and between 50 and 199 cells/microL [HR = 5.1 (1.6-16.3)], when compared with patients with CD4 count>350 cells/microL; AIDS events before HAART prescription [HR = 2.1 (1.2-3.7)]; CD8 count < 400 cells/microL [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/microL and AIDS events also have to be considered in the decision to initiate HAART.