Despite significant advancements in antiretroviral therapy (ART) for HIV, adherence remains a challenge. While Brazil has validated scales for treatment adherence, few assess treatment adherence barriers. This underscores the necessity for validated questionnaires on adherence barriers to identify patient-specific challenges and enhance strategies for ART adherence. This study aimed to adapt and validate the Adherence Barriers Questionnaire for HIV Patients on Antiretroviral Therapy (ABQ-HIV), a 17-item questionnaire assessing the adherence barriers to ART, for the Brazilian context and to evaluate its psychometric properties in HIV patients. A methodological study on the psychometric properties and factorial structure of ABQ-HIV was conducted. The study followed seven steps: consent of the original authors, two translations, synthesis of the translations, expert committee, back-translation, pre-test, and reliability test. A high content validity index (0.93) was achieved with the expert committee. The study sample consisted of 230 adults with HIV, with 37.0 (29.3-45.0) years as the median age (IQR), and 52.2% were male. The exploratory factor analysis with a three subscales structure of 17 items showed good interpretability (Bartlett's sphericity (1167.2 [136]; p < 0.001) and Kaiser-Meyer-Olkin = 0.602) and internal consistency (α = 0.76; Ω = 0.76). The fit indicators were satisfactory (χ2 = 89.931; df = 88; p > 0.005; RMSEA = 0.010; RMSR = 0.07; CFI = 0.996; GFI = 0.940; AGFI = 0.907; NNFI = 0.995). The Brazilian version of ABQ-HIV is a potential instrument for identifying specific barriers to adherence to ART in adults living with HIV in Brazil.
