Initial Antiretroviral Third-Drug Class and Time to Loss of Virologic Suppression: A Real-World Colombian Cohort Study

BackgroundReal-world comparisons of initial antiretroviral third-drug classes are limited in middle-income settings. We evaluated whether the initial third-drug class predicts time to loss of virologic suppression in Colombia.MethodsHistorical cohort of 609 ART-naïve adults (2016-2020). Outcome: first HIV RNA ≥200 copies/mL. We compared NNRTI, PI, and INSTI regimens using adjusted and IPTW-weighted Cox models.ResultsRegimens were NNRTI (72%), PI (20%), and INSTI (8%); 19.9% lost suppression. Compared with NNRTI, PIs showed higher but nonsignificant hazards (aHR 1.50, 95% CI 0.98-2.27). For INSTIs, we did not detect significant differences (aHR 1.22, 95% CI 0.64-2.31). Diagnosis-to-ART delays and treatment interruptions were associated with loss of suppression.ConclusionsTreatment continuity and timely initiation predicted sustained suppression better than drug class. Low INSTI usage limits statistical power to detect differences. Structural barriers to continuity may limit the real-world benefit of newer regimens.