Construct validity and internal consistency of the Patient Health Questionnaire-9 (PHQ-9) depression screening measure translated into two Ugandan languages

Background: In Uganda, depression is a major public health issue because of its direct disease burden and as a risk factor and co-morbidity for other pervasive health issues. Psychometric assessment of translated depression measures is critical to public health planning to ensure proper screening, surveillance, and treatment of depression and related outcomes. We examined aspects of the validity and reliability of the Patient Health Questionnaire-9 (PHQ-9) translated into Luganda and Runyoro in a large population-based cohort of Ugandan adolescents and adults.

Methods: Data from the ongoing open cohort AMBSO Population Health Surveillance study were analyzed from the Wakiso and Hoima districts in Uganda. Descriptive statistics were calculated for the overall sample and stratified by translated language. Construct validity was assessed for each translated scale using confirmatory factor analysis for ordinal data. The internal consistency of each translated scale was assessed using Cronbach's alpha, McDonald's omega total and omega hierarchical.

Results: Compared to the Runyoro-speaking subsample from Hoima (n=2297), participants in the Luganda-speaking subsample from Wakiso (n=672) were older (27 vs 21 years, p < 0.01) and a greater proportion were female (62% vs. 55%, p < 0.01). The Luganda-translated PHQ-9 had a sample mean of 3.46 (SD=3.26), supported a single-factor structure (RMSEA=0.05, CFI=0.96, TLI=0.94), and demonstrated satisfactory internal consistency (Cronbach's alpha=0.73, McDonald's omega total=0.76, McDonald's omega hierarchical=0.53). The Runyoro-translated PHQ-9 had a comparable sample mean of 3.58 (SD=3.00), also supported a one-factor structure (RMSEA=0.08, CFI=0.92, TLI=0.90), and demonstrated satisfactory internal consistency (Cronbach's alpha=0.72, McDonald's omega total=0.76, McDonald's omega hierarchical=0.57).

Conclusions: Our preliminary findings indicate that the Luganda and Runyoro translations of the PHQ-9 had satisfactory construct validity and internal consistency in our sample of Ugandan adolescents and adults. Future studies should expand on this promising work by assessing additional psychometric characteristics of these translated measures in other communities in Uganda.