CD4 cell counts at the third month of HAART may predict clinical failure

Objective: To evaluate the influence of immunological and virological markers on clinical outcome in patients receiving their first highly active antiretroviral therapy (HAART) regimen. Design and methods: Observational study of 585 patients initiating HAART in a clinical setting. Clinical failure was defined-as the occurrence of new or recurrent AIDS-defining events or death, and was analysed by means of intention-to-treat, univariate and multivariate analyses. An adjusted Cox regression model was used to evaluate the effect of 3-month CD4 cell counts on clinical outcome. Results: Clinical failure occurred in 55 patients (9.4%) during a median follow-up of 483 days (range 33-1334 days): 45 new AIDS-defining events (ADEs) in 38, ADE recurrence in six, and death in 11. Twenty-four of the 45 new ADEs (53.4%) occurred during the first 3 months of HAART, and 11 of 45 (24.4%) in the presence of CD4 cell counts >200 x 10(6) cells/l. The mean (median, range) CD4 counts were 144 x 10(6) cells/l (128, 4-529) in patients with and 322 x 10(6) cells/l (288, 14-1162) in patients without clinical failure (P < 0.0001). Moreover, the proportion of patients with mean CD4 cell counts < 200 x 10(6) cells/l was higher in those experiencing subsequent clinical failure (chi(2) test: 26.75; P < 0.00001). Multivariate analysis showed that baseline CD4 cell counts < 50 x 10(6) cells/l and AIDS at enrolment predicted failure; after adjusting for 3-month CD4 cell counts, this marker was the only one independently associated with clinical failure (hazard risk, 4.79; 95% confidence interval, 1.40-16.47). Conclusions: The 3-month immunological response is a reliable predictor of long term clinical outcome.