Nurses' well-being has been increasingly recognised due to the ongoing pandemic. However, no validation scales measuring nurses' well-being currently exist. Thus, we aimed to validate the WHO-5 Well-Being Index (WHO-5) in a sample of nurses. A cross-sectional multinational study was conducted, and a total of 678 nurses who worked during the COVID-19 pandemic in Spain (36.9%), Chile (40.0%) and Norway (23.1%) participated in this study. The nurses completed the WHO-5, the Patient Health Questionnaire-2 (PHQ-2), the Generalized Anxiety Disorder-2 (GAD-2) and three questions about the quality of life (QoL). The WHO-5 demonstrated good reliability and validity in the three countries. Cronbach's alphas ranged from 0.81 to 0.90. High correlations were found between the WHO-5 and the psychological well-being dimension of QoL, and negative correlations between the WHO-5 and PHQ-2. The unidimensional scale structure was confirmed in all the countries, explaining more than 68% of the variance. The item response theory likelihood ratio model did not show discernible differences in the WHO-5 across the countries. To conclude, the WHO-5 is a psychometrically sound scale for measuring nurses' well-being during a pandemic. The scale showed strong construct validity for cross-cultural comparisons; however, more research is required with larger sample sizes.
Keywords: COVID-19; WHO-5 Well-Being Index; cross-cultural; item response theory; measurement invariance; mental health; nursing staff; pandemics; public health; validation.