PURPOSE: Optimal asthma control can be difficult to achieve. We assessed the impact of asthma control on quality of life in a population with severe or difficult-to-treat asthma.
METHODS: We analyzed data from 987 subjects, age ≥18 years, enrolled in The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study. Asthma control was assessed using the Asthma Therapy Assessment Questionnaire (ATAQ), a validated index of control problems ranging from 0 to 4. Disease-specific quality of life and preference-based health utilities were assessed 12 months later using the Mini-Asthma Quality of Life Questionnaire (AQLQ) and EuroQol 5-D (EQ-5D), respectively. ANOVA was used to test for an overall difference among the levels of asthma control. General linear models were used to adjust for the effect of asthma severity and FEV<SUB>1</SUB> on the AQLQ and EQ-5D.
RESULTS: Mean AQLQ score was 5.3 ± 1.2. Mean EQ-5D-derived utility was 0.86 ± 0.16. Greater number of asthma control problems was associated with worse disease-specific quality of life (AQLQ score: 5.9 ± 0.9 [0 problems] to 3.9 ± 1.1 [4 problems]; p<0.0001) and lower health utilities (EQ-5D index: 0.91 ± 0.13 [0 problems] to 0.73 ± 0.21 [4 problems]; p<0.0001) over 12 months of prospective follow-up. In multivariable analyses adjusted for asthma severity and FEV<SUB>1</SUB>, number of control problems was a significant predictor of the AQLQ (p<0.0001) and EQ-5D (p<0.0001) at follow-up.
CONCLUSION: Poorer asthma control is associated with substantial quality of life impairment. Asthma control predicts quality of life even after taking into account asthma severity and lung function.
CLINICAL IMPLICATIONS: Asthma therapy and management strategies should strive for achieving optimal asthma control.
DISCLOSURE: Hubert Chen, Grant monies (from industry related sources) HC is supported in part through a research fellowship grant in the amount of $85,000 to the University of California, San Francisco (Cardiovascular Research Institute) from Genentech, Inc.