Symptoms and Health‒related Quality of Life of Patients with“Uncontrolled”Severe Asthma in Japan A Subanalysis of the Cross‒sectional ACQUIRE‒2 Study

Background：Few reports describe the epidemiology of severe asthma in Japan. This subanalysis of the ACQUIRE‒2 Study investigated the proportion and clinical characteristics of patients with“uncontrolled”severe asthma in Japan. 　　Methods：ACQUIRE‒2 was a multi‒center, observational study investigating asthma control, asthma symptoms and health‒related quality of life（HRQOL） among asthma patients（≧20 years）being managed by specialists. In this subanalysis, never smokers or smokers with＜10 pack‒years were included. Patients were classified into two groups：“severe asthma”and“mild‒to‒moderate asthma”. The severe asthma group was subdivided into“‘uncontrolled’severe asthma”and“not‘uncontrolled’severe asthma”based on a definition modified from the European Respiratory Society/American Thoracic Society guidelines. Asthma symptoms and HRQOL were evaluated. Results：Of the 870 patients included in the subanalysis, 205（23.6％）patients were confirmed as having severe asthma；among these, 107（12.3％）patients were classified as having“uncontrolled”asthma and 98（11.3％）patients were classified as having not “uncontrolled”asthma. Mean age, duration of asthma, and body mass index were 59.5±16.8 years, 23.2±16.6 years and 23.1±4.5 kg/m2, respectively, in the“uncontrolled” severe asthma group, and 57.2±12.6 years, 20.4±14.2 years and 23.0±4.0 kg/m2, respectively, in the not“uncontrolled”severe asthma group. Among 735 patients with available symptom information, in the“uncontrolled”severe asthma（n＝81）and not “uncontrolled”severe asthma（n＝84）groups, respectively, 60（74.1％）and 39（46.6％） patients experienced daytime asthma symptoms, 61（75.3％）and 33 （39.3％）experienced nighttime asthma symptoms, 22（27.2％）and 7（8.3％） experienced sleep disorders；20（24.7％）and 4（4.8％）experienced activity limitations. Among patients with“uncontrolled” severe asthma, 52.4％ had an asthma control questionnaire（ACQ‒5）score≧1.5；62.1％ of not “uncontrolled” severe asthma patients had a score of ≦0.75. Mean Mini Asthma Quality of Life Questionnaire scores for“uncontrolled”severe asthma and not“uncontrolled”severe asthma patients were 5.1±1.1 and 5.9±0.8, respectively. Conclusions：Among asthma patients managed by specialists in Japan, 12.3％ had “uncontrolled”severe asthma, were symptomatic, and had greater HRQOL impairment, suggesting a need for more effective asthma management options. Trial registration：ClinicalTrials. gov（NCT02640742）