Superior virologic and treatment outcomes when viral load is measured at 3 months compared to 6 months on antiretroviral therapy

• Published in: Journal of the International AIDS Society 2015-01, Vol.18 (1), p.20092-n/a
• Main Authors: Kerschberger, Bernhard, Boulle, Andrew M, Kranzer, Katharina, Hilderbrand, Katherine, Schomaker, Michael, Coetzee, David, Goemaere, Eric, Van Cutsem, Gilles
• Format: Article
• Language: English
• Subjects: Acquired immune deficiency syndrome; Adult; AIDS; AIDS/HIV; Ambulatory Care Facilities; Analysis; Anti-HIV Agents - therapeutic use; Antiretroviral agents; Antiretroviral drugs; Clinics; Cohort analysis; Data analysis; Drug resistance; Drug therapy; Epidemiology; Failure analysis; Female; Health aspects; Health Resources; HIV; HIV Infections - drug therapy; Human immunodeficiency virus; Humans; Infections; Low income groups; Male; Measurement; Middle Aged; Mortality; Patients; Pharmacoeconomics; Primary care; Public health; Retrospective Studies; Risk factors; Risk reduction; South Africa; Studies; Teenagers; Time Factors; Treatment Outcome; treatment switching; Viral load; Viral Load - drug effects; virologic failure
• ISSN: 1758-2652; 1758-2652
• DOI: 10.7448/IAS.18.1.20092

Introduction Routine viral load (VL) monitoring is utilized to assess antiretroviral therapy (ART) adherence and virologic failure, and it is currently scaled‐up in many resource‐constrained settings. The first routine VL is recommended as late as six months after ART initiation for early detection of sub‐optimal adherence. We aimed to assess the optimal timing of first VL measurement after initiation of ART. Methods This was a retrospective, cohort analysis of routine monitoring data of adults enrolled at three primary care clinics in Khayelitsha, Cape Town, between January 2002 and March 2009. Primary outcomes were virologic failure and switch to second‐line ART comparing patients in whom first VL done was at three months (VL3M) and six months (VL6M) after ART initiation. Adjusted hazard ratios (aHR) were estimated using Cox proportional hazard models. Results In total, 6264 patients were included for the time to virologic failure and 6269 for the time to switch to second‐line ART analysis. Patients in the VL3M group had a 22% risk reduction of virologic failure (aHR 0.78, 95% CI 0.64–0.95; p=0.016) and a 27% risk reduction of switch to second‐line ART (aHR 0.73, 95% CI 0.58–0.92; p=0.008) when compared to patients in the VL6M group. For each additional month of delay of the first VL measurement (up to nine months), the risk of virologic failure increased by 9% (aHR 1.09, 95% CI 1.02–1.15; p=0.008) and switch to second‐line ART by 13% (aHR 1.13, 95% CI 1.05–1.21; p