Asthma in USA: Its impact on health-related quality of life

Objectives: Given the growing prevalence of asthma in USA, it is important to understand its national burden from the patient's perspective. The objective of this research is to examine the national burden of asthma and poor asthma control on health function, health perception and preference-based health-related quality of life (HRQL). Methods: The Medical Expenditure Panel Survey (MEPS), a nationally representative survey, was used to estimate the impact of asthma and indicators of poor asthma control on health function, self-rated health perception and preference-based HRQL using multivariate regression methods controlling for socioeconomic, clinical and demographic characteristics. Two HRQL instruments were used: SF-12v2 Physical Component Scale (PCS-12) and Mental Component Scale (MCS-12); EQ-5D-3L index and visual analogue scale (VAS). Two multivariate regression methods were used, Censored Least Absolute Deviation [EQ-5D-3L and VAS (due to censoring)] and Ordinary Least Squares (OLS) (PCS-12 and MCS-12). Results: After controlling for covariates, asthma resulted in a statistically significant reduction in preference-based HRQL, health perception and physical and mental function (EQ-5D -0.023; VAS -2.21; PCS-12 -2.36; MCS-12 -0.96). Likewise, experiencing an exacerbation in the previous year and using more than three canisters of quick-relief medication in the previous 3 months were both associated with a statistically significant and clinically meaningful reduction in all four measures. Conclusions: Asthma itself and especially indicators of poor asthma control were associated with a deleterious effect on health function, preference-based HRQL and self-perceived health status. Given the prevalence of asthma, poorly controlled asthma constitutes a significant national burden in USA.