Validation of the combined Patient Health Questionnaire Anxiety and Depression Scale among people with HIV in Vietnam.

BACKGROUND: Our study aims to examine the factor structure, validity, and reliability of the combined scale Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS) among people with HIV (PWH) in Vietnam. METHODS: Baseline data from an alcohol-reduction intervention trial among ART clients in Thai Nguyen, Vietnam were used for this analysis (n = 1547). A score ≥10 on the PHQ-9, GAD-7 and PHQ-ADS scale was considered having clinically meaningful depression, anxiety and distress symptoms. Factor structure of the combined PHQ-ADS scale was validated using confirmatory factor analysis, and three models were tested: a one-factor, a two-factor, and a bi-factor model. Reliability and construct validity were examined. RESULTS: The prevalence of clinically meaningful depression and anxiety symptoms was 7% and 2%, respectively, while 19% had distress symptoms. A bi-factor model had the best fit to the data (RMSEA = 0.048; CFI = 0.99; TLI = 0.98). The Omega index of the bi-factor model was 0.97. The scale showed good construct validity through negative associations between depression, anxiety, distress symptoms and quality of life. CONCLUSIONS: Our study supports the use of a combined scale to measure general distress for PWH, which has good validity, reliability and is unidimensional enough to justify the use of a composite depression and anxiety score.