Predictors of virologic failure in HIV-1-infected patients starting highly active antiretroviral therapy in Porto Alegre, Brazil

Abstract

Objective: To assess predictors of virologic response 6 months after initiation of highly active antiretroviral therapy (HAART) in a cohort of HIV-infected patients in Brazil.

Methods: Treatment-naive patients who started HAART between 1996 and 2004 and had information on viral load at 3-9 months were included. Information was collected on demographic characteristics, antiretroviral regimen, adherence, AIDS diagnosis, baseline CD4 cell count, and viral load. Virologic failure (VF) was defined as viral load > or =400 copies/mL at 6 months or death before completion of 6 months of therapy.

Results: Among 454 patients who met the inclusion criteria, VF occurred in 127 (28.0%). In univariate analysis, VF was associated with younger age (median 34 vs. 37 years, P = 0.003), AIDS diagnosis (relative risk [RR] 1.18, P = 0.009), higher baseline viral load (5.34 vs. 5.00, P = 0.0002), lower baseline CD4 cell count (86 vs. 182, P = 0.006), nonadherence (RR 1.39, P < 0.0001), regimen containing 1 single protease inhibitor, as compared with ritonavir-boosted regimens (odds ratio [OR] 8.5, P < 0.0001), and year therapy initiated before 1999 (P < 0.0001). To minimize the systematic effect of therapy indication, we analyzed the subset of 158 patients with CD4 count < or =200 cells/microL who started therapy after 1999. After adjusting for age, education, adherence, regimen, and baseline viral load, nonadherence (OR 8.78, P = 0.02), and fewer years of education (OR 6.05, P = 0.05) remained associated with VF.

Conclusions: A significant improvement was found in virologic suppression over time, consistent with the introduction of nonnucleoside reverse transcriptase inhibitors and ritonavir-boosted regimens into clinical practice. With currently available therapies, compliance and education were shown to be predictors of virologic response, particularly in more immunocompromised patients.