RESUMO
BACKGROUND: Antiretroviral therapy (ART) regimen failure is linked to an increased risk of disease progression and death, while early detection of ART failure can help to prevent the development of resistance. This study aimed to evaluate virological and immunological ART failure and predictors among HIV-positive adult and adolescent clients in southeast Ethiopia. METHODS: A retrospective cohort study was implemented from January 2016 to November 30, 2020; all HIV-positive nave patients on follow-up during the study period from four hospitals were included. Virological and immunological treatment failure was the primary outcome of the study. Cox proportional hazards regression models were employed for analysis. Hazard ratios with 95% confidence intervals were reported and variables with p-values <0.05 were considered statistically significant predictors of treatment failure. RESULTS: A total of 641 HIV patients' charts were reviewed, 62.6% of the study participants were females. Of the total study participants, 18.4% and 15% developed virological and immunological ART regimen treatment failure respectively. The median time to virological failure was 40 months. WHO stage IV [AHR = 4.616; 95% CI: (2.136-9.974)], WHO stage III [AHR = 2.323; 95% CI: (1.317-4.098)], poor adherence to HAART regimen [AHR = 3.097; 95% CI: (1.349-7.108)], and fair adherence [AHR = 2.058; 95% CI: (1.234-3.432)] were significantly associated with virological treatment failure among adolescent and adult study participants in southeast Ethiopia. CONCLUSION: The prevalence of virological treatment failure was 18.4% (95% CI: 15.4 -21.4) and the prevalence of immunological treatment failure was 15% (95% CI: 11.8-18.4). WHO clinical stage III/IV and non-adherence were independent predictors of virological ART treatment failure. Early management of clinical WHO stages and improving patients' ART regimen adherence are important to decrease the prevalence of ART regimen treatment failure.