Abstract
Background: The limited access to virological monitoring in developing countries is a major weakness of the current antiretroviral treatment (ART) strategy in these settings. We conducted a large cross-sectional study in Burkina Faso, Cameroon, Cote d'Ivoire, Senegal, Togo, Thailand, and Vietnam to assess virological failure and drug resistance mutations (DRMs) after 12 or 24 months of ART.Methods: Between 2009 and 2011, we recruited adults attending ART centers 10-14 months (the M12 group) or 22-26 months (M24 group) after initiating ART. Demographic and clinical data were collected on site, and viral load was measured. Samples with a viral load of ≥ 1000 copies/mL, considered as the failure threshold, were genotyped for drug resistance assessment.Results: Overall, 3935 patients were recruited (2060 at M12 and 1875 at M24). Median ages varied from 32 to 42 years. Median CD4(+) T-cell counts at ART initiation were low (99-172 cells/µL). The main ART regimens included stavudine/zidovudine plus lamivudine plus nevirapine/efavirenz. Overall, virological failure frequency was 11.1% for M12 patients and 12.4% for M24 patients, and 71.0% to 86.1% of these patients, respectively, had drug-resistant virus. Across sites, virological failure varied from 2.9% to 20.6% in M12 patients and from 3.7% to 26.0% in M24 patients. Predominant DRMs were associated with ART regimens, but virus in several patients accumulated DRMs to drugs not received, such as abacavir, didanosine, tenofovir, etravirine, and rilpivirine.Conclusions: Our findings show heterogeneous virological failure and illustrate that, in addition to routine access to viral load, good management of ART programs is even more critical to improve treatment outcomes in resource-limited countries.