Abstract
Background
Antiretroviral 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.
Results
We followed 4,718 clients for 15,100 person-years (PY) of observations. Of them, 1,402 experienced virologic failure, equivalent to 29.72% 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).
Conclusions
In Tanzania, approximately 30% of the adult clients on second-line ART experience VF at a rate of 92.71 per 1000 person-years. This high virologic failure rate highlights the need for targeted interventions for HIV-infected clients on second-line ART to reduce the need for switching to the more costly and relatively more toxic third-line ART therapy and help to achieve the third UNAIDS goal of achieving viral suppression for 95% of those treated by 2030.