The reliability, validity and factorial structure of the Swahili version of the 7-item generalized anxiety disorder scale (GAD-7) among adults living with HIV from Kilifi, Kenya.
Nyongesa MK., Mwangi P., Koot HM., Cuijpers P., Newton CRJC., Abubakar A.
BACKGROUND: Generalized Anxiety Disorder (GAD) is under-investigated in people living with HIV/AIDS from sub-Saharan Africa. In part, this is due to paucity of culturally appropriate measures for GAD which are psychometrically robust. This study aimed to evaluate the reliability, factorial structure, and validity of Swahili version of the 7-item GAD questionnaire (GAD-7) among adults living with HIV. STUDY DESIGN: Descriptive cross-sectional study. METHODS: 450 adults receiving comprehensive care from an HIV specialized clinic in Kilifi County, coastal Kenya, were consecutively recruited. Swahili versions of GAD-7, Patient Health Questionnaire (PHQ-9) and a 12-item HIV stigma scale were administered alongside measures of psychosocial and health-related characteristics. Internal consistency, test-retest reliability, factorial structure, convergent validity, and discriminant validity of Swahili GAD-7 were examined using Cronbach's alpha (α), intra-class correlation coefficient (ICC), Confirmatory Factor Analysis (CFA), Pearson's correlation, and analysis of covariance (ANCOVA), respectively. RESULTS: Internal consistency of Swahili GAD-7 was good, α = 0.82 (95% CI 0.78, 0.85). Its test-retest reliability (2 weeks apart) was acceptable, ICC = 0.70 (95% CI 0.55, 0.81). A confirmatory analysis of a one-factor solution indicated an excellent fit to the hypothesized structure (RMSEA = 0.00 [95% confidence interval 0.00, 0.05], CFI = 1.00, TLI = 1.00). Multi-group CFA substantiated factorial invariance for sex and age for the one-factor structure of Swahili GAD-7. Scores of GAD-7, Swahili version, significantly correlated with those of PHQ-9 (r = 0.73; p