Impact of allergies on health-related quality of life in patients with asthma.

Objective: To estimate the health-related quality of life (HRQoL) and health utilities among asthma patients with and without comorbid allergies in a managed care population. Methods: This was a retrospective analysis of patient survey responses and pharmacy claims from the Observational Study of Asthma Control and Outcomes (OSACO). Patients >= 12 years-old with persistent asthma received four identical surveys between April-2011 and December-2012. The presence of allergy was identified by a positive response to a survey question about hay fever/seasonal allergies and >= 1 diagnosis-related ICD-9-CM code(s) for allergic conditions. HRQoL instruments included generic utility (EQ-5D-3L [including VAS]), asthma-specific utility (AQL-5D) and asthma-specific health status (Mini Asthma Quality of Life Questionnaire [MiniAQLQ]). Median regression was used for utility scores and Least Squares regression for MiniAQLQ, adjusting for sociodemographic characteristics and smoking. Results: Of the 2681 asthmatics who completed the first survey in the OSACO study, 971 had comorbid allergies. After adjusting for covariates, asthma patients with comorbid allergies had significantly lower MiniAQLQ scores than patients without allergies (-0.489 [95% CI -0.570, -0.409]; p < 0.01), with the greatest decrement/impairment observed for the environmental stimuli domain (-0.729 [95% CI -0.844, -0.613]; p < 0.01). Utility scores were also statistically significantly lower for asthma patients with comorbid allergies compared to those without allergies (EQ-5D, -0.031 [95% CI -0.047, -0.015]; AQL-5D, -0.036 [95% CI -0.042, -0.029]; p < 0.01 each). Conclusions: The presence of allergies with persistent asthma is associated with a significant deleterious impact on several different measures of HRQoL.