Utilities for asthma and COPD according to category of severity: a comprehensive literature review.

Background: Asthma and chronic obstructive pulmonary disease (COPD) are incurable diseases that impact quality-of-life.
Objective: To summarize original research articles that measured or utilized preference-based utilities or disutilities according to disease severity.
Methods: Medline and Embase were searched from inception until the end of November 2014. Two reviewers independently searched the literature with differences settled through discussion. Data extracted included utility scores as determined in original research categorized according to disease severity as well as disutilities associated with exacerbations or comorbidities. Data were tabulated and analyzed descriptively.
Results: In total, 862 articles were identified, 790 were rejected, and 69 analyzed. There were 44 dealing with COPD and 25 with asthma. Average utilities determined by research were 0.828 ± 0.062, 0.765 ± 0.090, 0.711 ± 0.120, and 0.607 ± 0.120 for mild, moderate, severe, and very severe COPD, respectively. Utilities used in economic analyses were 0.866 ± 0.038, 0.770 ± 0.024, 0.739 ± 0.045, and 0.596 ± 0.075, respectively. Disutilities (annual) ranged from 0.002-0.378; major and minor exacerbations had respective disutilities of 0.287 and 0.108. For asthma patients, utilities were for 0.86 ± 0.32, 0.83 ± 0.065, and 0.74 ± 0.029, for mild, moderate, and severe disease, respectively.
Conclusions: Utilities have been summarized according to severity category of asthma and COPD. These values should be useful for researchers undertaking economic analyses of these diseases.