Impact of adherence and highly active antiretroviral therapy on survival in HIV-infected patients

Objectives: To assess the effect of antiretroviral therapy (ART) adherence on survival in HIV-infected patients. Design: Cohort study at a single hospital in Barcelona, Spain. Methods: Data on HIV-infected patients older than 18 years of age who began ART during the period 1990 to 1999 were analyzed. Patients were considered nonadherent if the total dose of antiretroviral drug was less than 90% of that prescribed. Adherence was assessed through self-report and hospital pharmacy appointments. Cox regression with time-dependent variables was used. Results: A total of 1219 patients were included. The first ART was with monotherapy in 23.7% of cases, with two drugs in 30.5%, and with triple therapy in 45.8%. In multivariate analysis, the variables that presented significant differences with respect to mortality were clinical stage at the beginning of treatment (AIDS: relative hazard (RH) = 2.97; 95% confidence interval [CI]: 2.14-4.13), CD4 cell count (<200 cells/μL: RH = 5.89; CI: 3.44-10.10), type of treatment (monotherapy: RH = 9.76; Cl: 4.56-20.90; bi-therapy: RH = 9.12; CI: 4.23-19.64), and adherence (nonadherence: RH = 3.87; CI: 1.77-8.46). Conclusions: The modifiable factors most strongly associated with survival were type of treatment and adherence. It would be desirable to accompany therapy with intervention strategies intended to improve adherence.