Predictors of virological rebound in HIV-1-infected patients initiating a protease inhibitor-containing regimen

Objective: To study the predictors of virological rebound in patients having early virological response to protease inhibitor (PI)-containing regimen. Design and methods: APROCO cohort study prospectively enrolled 1283 HIV-infected patients starting a PI-containing regimen in 1997-1999. Adherence to therapy was measured with self-administered questionnaires after 4 months of therapy (M4). Virological rebound was defined as a viral load (VL) > 500 copies/ml in patients having early virological response, defined as a VL < 500 copies/ml at M4. Predictors of time to virological rebound were studied with multivariate proportional hazards model. Results: During a median follow-up of 20 months, virological rebound was observed in 32% of the 830 patients with early virological response. Virological rebound was more frequent when patients had received previous antiretroviral treatment [adjusted hazards ratio (HR) = 2.4; P < 0.0001], were younger (HR = 1.4 per each 10 years younger; P < 0.0001), had baseline CD4 cell count < 500 x 10(6)/l (HR = 2.3; P < 0.001), had higher baseline VL (HR = 1.4 per each log(10) copies/ml higher; P < 0.001), reported low adherence to therapy at M4 (HR = 2.1; P < 0.001) or had stopped PI at M4 (HR = 1.7; P = 0.04). Conclusion: Initiation of treatment at a stage of preserved immunity is associated with a more durable virological response under protease inhibitor. Every effort should be made to monitor and strengthen adherence to therapy, even in patients having early virological response. (C) 2002 Lippincott Williams Wilkins.