Relationship between health-related quality of life and subjective wellbeing in asthma

Objective: Poor health-related quality of life (HRQoL) is associated with a high risk of acute exacerbations in patients with asthma. The use of health state utility instruments to measure HRQoL is common, but it has been criticised for failing to adequately capture the impact of the condition from the patient perspective. We aimed to assess the ability of subjective wellbeing and health state utility instruments to capture important HRQoL dimensions for asthma patients. Methods: Regression analyses were conducted using data (n = 856 asthma patients) from a large multi-national cross-sectional survey to explore the relationship between subjective wellbeing (ONS4, PWI, SWLS), health state utility (15D, AQoL-8D, EQ-5D-5L, HUI3, SF-6D, SF-6Dv2), and an asthma-specific instrument (AQLQ-S). The latent structure of different instruments was investigated using an exploratory factor analysis. Results: All instruments could distinguish the impact of asthma on HRQoL. Among health utility instruments, 15D, SF-6D and AQoL-8D were more sensitive based on the average standardised regression coefficients. AQOL-8D had the strongest correlation with subjective wellbeing. Nevertheless, the exploratory factor analysis showed a complementary relationship between subjective wellbeing and HRQoL instruments. The most important subjective wellbeing domains were standard of living, achieving in life, and personal relationships; although contributions of these domains to overall life satisfaction differed among asthma patients identified by a latent class analysis. Conclusion: The use of subjective wellbeing alongside AQLQ-S and health state utility instruments provides a comprehensive approach to assess the impact of asthma on the patient's life. Further research is needed to incorporate these measures in health care evaluation.