ABSTRACTObjectiveTo compare viral suppression in treatment-naïve adults starting antiretroviral therapy with dolutegravir (50mg)- and efavirenz (600mg)-based regimens.MethodsWe analyzed secondary data from Brazilian health information systems of people living with human immunodeficiency virus who started antiretroviral therapy between 2015 and 2017 in Minas Gerais, Brazil. The outcome was viral suppression, defined as the achievement of the first viral load <50 copies/mL within 12 months after initiating antiretroviral therapy. This outcome was also compared with viral load <1,000 copies/mL and analyzed in two scenarios: intention-to-treatversusper-protocol. Time to viral suppression and adjusted odds ratio accompanied by 95% confidence intervals were estimated.ResultsOf the 2,599 participants enrolled, 77.5% were men, and the median age was 34 years. In the intention-to-treat analysis, viral suppression was 58.1% for efavirenz and 76.7% for dolutegravir. People living with HIV on dolutegravir-based regimen were more likely to achieve viral suppression (aOR: 2.44; 95%CI: 2.01-2.95) and had a shorter median time to viral suppression (p<0.0001). Antiretroviral therapy initiation within <120 days, baseline CD4⁺T-cells ≥200 cells/mm3, and viral load <100,000 copies/mL had higher odds of viral suppression. According to the per-protocol analysis, viral suppression ≥90% was observed by considering viral load <1,000 copies/mL.ConclusionOur study demonstrated that viral suppression improved after introducing dolutegravir, although the proportion of patients with viral load <50 copies/mL was lower than expected. Improved access to routine viral load examinations and continuous surveillance of the effectiveness of antiretroviral therapy should be considered.