Measurement Properties and Optimal Cutoff Point of the WHO-5 Among Chinese Healthcare Students

Abstract

Purpose: The World Health Organization-Five Well-Being Index (WHO-5) is widely used to assess subjective well-being. Nevertheless, measurement invariance and optimal cutoff point of the WHO-5 have not been examined in Chinese samples. We aimed to assess measurement properties of the Chinese version of the WHO-5 (WHO-5-C) among healthcare students. Patients and Methods: A two-wave longitudinal assessment was conducted among 343 Chinese healthcare students from September to November 2022. Measurement properties of the WHO-5-C were assessed through structural validity using confirmatory factor analysis (CFA), measurement invariance using multigroup CFA (MGCFA) and longitudinal CFA (LCFA), convergent validity using correlation analysis with the Self-Rated Health Questionnaire (SRHQ) and Patient Health Questionnaire-4 (PHQ-4), reliability using internal consistency and test–retest reliability, and optimal cutoff point using receiver operating characteristic (ROC) analysis. Results: The WHO-5-C demonstrated satisfactory structural validity with comparative fit index (CFI) of 0.968 at baseline and 0.980 at follow-up, and adequate measurement invariance in different sociodemographic variables at baseline (gender, age, major, home location, being only child, monthly household income, part-time job, physical exercise, hobby, frequency of visiting home, and stress coping strategy) (CFI changes [ΔCFI] = −0.009–0.003) and over a week (ΔCFI = −0.006–0.000). The WHO-5-C also had good internal consistency (Cronbach’s α = 0.907–0.934; McDonald’s ω = 0.908–0.935) and test–retest reliability (intraclass correlation coefficient [ICC] = 0.803). Convergent validity was supported by moderate correlations of the WHO-5-C with the SRHQ and PHQ-4. The optimal cutoff point of the WHO-5-C was found to be 50, with an area under the ROC curve of 0.882 at baseline data, with sensitivity of 0.803 and specificity of 0.762 at follow-up. Conclusion: The WHO-5-C demonstrated adequate measurement properties, especially concerning cross-sectional and longitudinal measurement invariance, with a recommended optimal cutoff point of ≥ 50 for assessing adequate level of psychological well-being in healthcare students.