Prevalence, rate, and predictors of virologic failure among adult HIV-Infected clients on second-line antiretroviral therapy (ART) in Tanzania (2018–2020): a retrospective cohort study

Abstract

BackgroundAntiretroviral therapy (ART) has been proven to be highly effective in reducing the impact of human immunodeficiency virus (HIV) infection. However, as more people receive initial ART treatment, the risk of developing resistance and eventual treatment failure increases, leading to the need for second-line treatment regimens. Understanding the factors that contribute to virologic failure to second-line ART is crucial in preventing switching to the more expensive and toxic third-line regimens. This study provides information on the prevalence, rate, and predictors of virologic failure (VF) among clients on second-line ART in Tanzania.ResultsWe followed 4718 clients for 15100 person-years (PY) of observations. Of them, 1402 (29.72%) experienced virologic failure at a rate of 92.85 per 1000 PY of observations (95% CI 88.11, 97.84). Factors that were associated with VF included: having a viral load count of ≥ 1000 copies/mL during first-line ART, with a hazard ratio (HR) 4.65 (95% CI 3.57, 6.07), using lopinavir (LPV/r) as a protease inhibitor during second-line ART (HR 4.20 (95% CI 3.12, 7.10), having a CD4 count < 200 cells/mm3 during second-line ART (HR 1.89 (95% CI 1.46, 2.44), and being on ART for 13–35 months (HR 8.22 (95% CI 2.21, 30.61). Paradoxically, having a CD4 count < 200 cells/mm3 during first-line ART treatment was associated with a reduced risk of virologic failure (HR 0.77 (95% CI 0.60, 0.99).ConclusionsIn Tanzania, approximately 30% of adult clients on second-line ART experience VF at a rate of 92.71 per 1000 person-years. This high virologic failure rate underscores the urgent need for targeted interventions, such as enhancing adherence support, optimizing drug regimens, and regular viral load monitoring. These interventions will reduce the need for switching to the more costly and toxic third-line ART therapy and are also crucial for achieving the UNAIDS goal of 95% viral suppression among treated individuals by 2030.