Development of a questionnaire to evaluate asthma control in Japanese asthma patients.

BACKGROUND: The asthma control questionnaires used in Japan are Japanese translations of those developed outside Japan, and have some limitations; a questionnaire designed to optimally evaluate asthma control levels for Japanese may be necessary. The present study was conducted to validate the Japan Asthma Control Survey (JACS) questionnaire in Japanese asthma patients. METHODS: A total of 226 adult patients with mild to severe persistent asthma were enrolled and responded to the JACS questionnaire, asthma control questionnaire (ACQ), and Mini asthma quality of life questionnaire (Mini AQLQ) at Weeks 0 and 4. The reliability, validity, and sensitivity/responsiveness of the JACS questionnaire were evaluated. RESULTS: The intra-class correlation coefficients (ICCs) were within the range of 0.55-0.75 for all JACS scores, indicating moderate/substantial reproducibility. For internal consistency, Cronbach's alpha coefficients ranged from 0.76 to 0.92 in total and subscale scores, which were greater than the lower limit of internal consistency. As for factor validity, the cumulative contribution ratio of four main factors was 0.66. For criterion-related validity, the correlation coefficients between the JACS total score and ACQ5, ACQ6, and Mini AQLQ scores were -0.78, -0.78, and 0.77, respectively, showing a significant correlation (p < 0.0001). CONCLUSIONS: The JACS questionnaire was validated in terms of reliability and validity. It will be necessary to evaluate the therapeutic efficacy measured by the JACS questionnaire and calculate cutoff values for the asthma control status in a higher number of patients. CLINICAL TRIAL REGISTRATION: UMIN000016589.