Diversified antiretroviral therapy (ART) approach is needed in methods that were acceptable to communities and maintain good viral suppression outcomes to reach the UNAIDS targets to end the HIV/AIDS epidemic by 2030. Ethiopia is fully implementing differentiated service delivery (DSD) approaches, appointment spacing, and standard care. This study aimed to determine the time to HIV virological failure and its predictors among patients with a DSD model. An institution-based retrospective cohort study was conducted with data collection dates ranging from May 1, 2021, to May 30, 2021. All adult HIV-positive patients (n = 2,148) between January 2018 and January 2021 were a source population. Data were extracted using a standard checklist by trained data collectors and entered into EpiData, exported to SPSS version 20 for data management, and then exported to R Studio version 1.4 for analysis. Kaplan-Meier survival curves, the log-rank test, and Cox proportional hazard regression models were employed. The incidence of virological failure was 86 per 10,000 person-months. The independent predictors for the hazard of virological failure were being on standard care [adjusted hazard ratios (AHR) = 1.91; 95% confidence interval (CI) 1.07-3.40], primarily educated (AHR = 3.46; 95% CI 1.02-11.72), having no education (AHR = 3.45; 95% CI 1.01-11.85), and ambulatory status at baseline (AHR = 1.81; 95% CI 1.06-3.09). Patients who had a viral load with a detectable range from 50 to 999 at engagement (AHR = 2.65; 95% CI 1.33-5.27) and a 1-month increase in ART for HIV patients (AHR = 1.045; 95% CI 1.01-1.09). The incidence of virological failure was 86 per 10,000 person-months, whereas the incidences were 52 per 10,000 person-months and 71 per 10,000 person-months on appointment spacing model and standard care, respectively, with independent predictors: patient category, educational status, baseline functional status, viral load at engagement, and duration of ART.
Keywords: Ethiopia; HIV/AIDS; UNAIDS; appointment spacing; differentiated care; treatment failure.