Association of baseline advanced HIV disease and dolutegravir versus non-dolutegravir regimen status with viral load suppression among patients on antiretroviral therapy in Tanzania

Abstract Background Dolutegravir (DTG)-based regimens are currently the preferred first-line therapy in many HIV programs; however, the influence of baseline advanced HIV disease (AHD) on virologic outcomes in routine national data in the DTG era remains unclear. Methods We conducted a retrospective cohort analysis using routinely collected data from Tanzania’s National AIDS, STIs, and Hepatitis Control Programme (NASHCoP) database (2017-2021). A simple random sample of 50,000 patients was drawn from the de-duplicated national dataset, yielding 49,863 patients after data processing. The analytic cohort included 4,044 patients with baseline CD4 and endpoint viral load measurements. Viral load suppression was defined as <1000 copies/mL. Associations between baseline AHD, regimen status, and suppression were assessed using risk ratios and multivariable Poisson regression models, including an interaction term between AHD and DTG. Results Overall viral load suppression was 89.2% (3,607/4,044). Patients with baseline AHD had lower suppression than those without AHD (81.3% vs. 91.1%; RR 0.48, 95% CI 0.40-0.57). Suppression was higher among patients receiving DTG-based regimens than among those receiving non-DTG regimens (91.5% vs. 77.2%; RR 2.67, 95% CI 2.23-3.20). In the adjusted analysis, baseline AHD remained associated with reduced suppression (aRR 0.89, 95% CI 0.86-0.92), whereas DTG use was associated with improved suppression (aRR 1.15, 95% CI 1.10-1.20). A significant interaction between AHD and DTG was observed (aRR 1.40, 95% CI 1.20-1.63), indicating that the relative benefit of DTG was greater among patients with baseline AHD. Conclusions Although viral load suppression was high in this Tanzanian routine-care cohort, patients with baseline AHD had poorer outcomes. DTG-based regimens were associated with improved overall suppression, with a greater relative benefit among patients with advanced disease. These findings support the continued prioritization of DTG-based therapy and reinforce the importance of early diagnosis and targeted management of patients with AHD.