Validation Study of a Disease-specific Module, the Asthma Health Questionnaire (AHQ) Using Japanese Adult Asthmatic Patients

ABSTRACT Background An asthma-specific questionnaire, the Asthma Health Questionnaire (AHQ) was developed for Japanese asthmatic patients. A self-administered 37-item version (AHQ-37) consisting of 36 disease-specific items and a Face Scale was designed for socially active patients. Methods Exploratory factor analysis, test-retest reliability, internal consistency, concurrent validity and longitudinal validity were evaluated. A total of 326 asthma patients (202 men; range of age from 18 to 65 years) answered the AHQ-37 twice. Results Each item of the AHQ-37 was well accepted by the patients with answering rates of 95 to 100%. Six subscales (Asthmatic Symptoms, Emotion, Daily Activity, Factors which Worsened Symptoms, Social Activity and Economics) were extracted by factor analysis. Psychometric testing showed high feasibility, good repeatability and good internal consistency. The Face Scale moderately correlated with all subscales except for Economics, indicating that the Face Scale alone could measure global quality of life (QOL) functioning of asthmatic patients. Concurrent validity with peak-flow values was insufficient (Spearman’s correlation coefficient = 0.05−0.27), showing that the peak flow alone could not estimate QOL. In longitudinal validity, however, changes in peak-flow values had an impact on the Asthmatic Symptoms, Daily Activity and Factors which Worsened Symptoms ( P = 0.000−0.419), indicating that changes in peak-flow were important to asthmatic patients’ QOL. Conclusions The QOL of asthmatic patients must be evaluated by asthma-specific questionnaires, such as the AHQ-37.