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

To evaluate the influence of immunological and virological markers on clinical outcome in patients receiving their first highly active antiretroviral therapy (HAART) regimen.

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.

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 (X2 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).

The 3-month immunological response is a reliable predictor of long-term clinical outcome.