Virologic Failure Rates Vary Substantially Across Countries in Africa and Asia

Salim S. Abdool Karim, MD, PhD

A cross-sectional study has shown wide disparity in virologic-failure rates across countries, primarily reflecting different prevalences of drug-resistance mutations.

Although access to antiretroviral therapy (ART) in resource-limited settings has improved, poor treatment outcomes and the emergence and transmission of drug-resistant viruses remain important challenges that could undermine programmatic successes. The WHO public health approach (i.e., standardization of ART services through use of clinical/immunological criteria only for ART initiation or switch, limited access to virologic monitoring, and use of low–genetic barrier drugs) may favor the rapid emergence, spread, and transmission of resistant viruses.

In a recent cross-sectional study, researchers evaluated treatment outcomes, including virologic failure and drug resistance, among patients attending ART services in seven resource-limited countries that had adopted the WHO approach. From October 2009 through December 2011, patients in sub-Saharan Africa and Southeast Asia were recruited at 12 (n=2060) or 24 months (n=1875) after ART initiation. All were still receiving a first-line regimen.

Overall rates of virologic failure (viral load ≥1000 copies/mL) after 12 months and 24 months were 11.1% and 12.4%, respectively. Stratification by center revealed considerable variation in these rates at both time points (month 12, 2.9%–20.6%; month 24, 3.7%–26.0%). Among patients with virologic failure, 71.0% and 86.1% had drug-resistant viruses after 12 and 24 months.

In the five countries with the highest virologic-failure rates, 18% to 43% of patients with such failure had no resistance mutations, suggesting suboptimal ART adherence. Although most drug-resistance mutations identified were related to medications the patients were taking, some mutations conferred resistance to second-line ART drugs, highlighting the importance of drug-resistance testing during the course of treatment.

Citation(s):

Aghokeng AF et al. Extraordinary heterogeneity of virological outcomes in patients receiving highly antiretroviral therapy and monitored with the World Health Organization public health approach in Sub-Saharan Africa and Southeast Asia. Clin Infect Dis 2013 Sep 27; [e-pub ahead of print].