OBJECTIVE: The 5-item World Health Organization well-being index is a commonly used measure of emotional well-being, but research on psychometric properties in outpatients with diabetes is scarce. We examined psychometric and screening properties for depression of this index in a large sample of Dutch outpatients with diabetes.
METHODS: Patients with Type 1 (n = 384) and Type 2 (n = 549) diabetes from three outpatient clinics completed the WHO-5 index, the nine-item Patient Health Questionnaire, the Problem Areas in Diabetes survey and the Short Form-12 health survey. Internal consistency of the WHO-5 index was determined by Cronbach's alpha. The factor structure was tested by confirmatory factor analysis. Concurrent validity was assessed by correlations with the Patient Health Questionnaire, Problem Areas in Diabetes and the Short Form-12 mental component scores. Sensitivity and specificity of the WHO-5 index as depression screener were tested against two existing Patient Health Questionnaire cut-off scores for depression using receiver operating characteristic curves.
RESULTS: A one-factor structure of the WHO-5 index was verified by confirmatory factor analysis for patients with Type 1 and Type 2 diabetes. Moderate to strong correlations were observed between the WHO-5 index and the Patient Health Questionnaire scores, the Problem Areas in Diabetes scores and the Short Form-12 mental component scores (r = 0.55-0.69, P < 0.001). Receiver operating characteristic curves showed that a WHO-5 index cut-off of < 50 performed best as an indication for likely depression, with sensitivity compared with a Patient Health Questionnaire score ≥ 10 and ≥ 12 of 79% and 88%, respectively, and specificity of 88% and 76%, respectively.
CONCLUSIONS: The WHO-5 index is a short, psychometrically sound measure of emotional well-being that appears suitable for use as screening test for likely depression in outpatients with Type 1 and Type 2 diabetes.