Background: Early initiation of highly active antiretroviral therapy (HAART) decreases human immunodeficiency virus- (HIV-) related complications, restores patients' immunity, decreases viral load, and substantially improves quality of life. However, antiretroviral treatment failure considerably impedes the merits of HAART.

Objective: This study is aimed at determining the prevalence of immunologic and clinical antiretroviral treatment failure.

Methods: A cross-sectional study design using clinical and immunologic treatment failure definition was used to conduct the study. Sociodemographic characteristics and clinical features of patients were retrieved from patients' medical registry between the years 2009 and 2015. All patients who fulfilled the inclusion criteria in the study period were studied. Predictors of treatment failure were identified using Kaplan-Meier curves and multivariable Cox regression analysis. Data analysis was done using SPSS version 21 software, and the level of statistical significance was declared at a p value < 0.05.

Results: A total of 770 were studied. The prevalence of treatment failure was 4.5%. The AZT-based regimen (AHR = 16.95, 95% CI: 3.02-95.1, p = 0.001), baseline CD4 count ≥ 301 (AHR = 0.199, 95% CI: 0.05-0.76, p = 0.018), and bedridden during HAART initiation (AHR = 0.131, 95% CI: 0.029-0.596, p = 0.009) were the predictors of treatment failure.

Conclusion: The prevalence of treatment failure was lower with the risk being higher among patients on the AZT-based regimen. On the other hand, the risk of treatment failure was lower among patients who started HAART at baseline CD4 count ≥ 301 and patients who were bedridden during HAART initiation. We recommend further prospective, multicenter cohort studies to be conducted to precisely detect the prevalence of treatment failure using viral load determination in the whole country.