Comparison of the Asthma Health Questionnaire-33-Japan and the short-form 36-item health survey for measuring quality of life in Japanese patients with asthma.

Background: The Asthma Health Questionnaire (AHQ)-Japan is useful for assessing quality of life (QOL) in Japanese patients with asthma. However, no studies have compared the AHQ-Japan to other QOL instruments.
Methods: The AHQ-33-Japan and the Medical Outcomes Study Short-Form 36-Item Health Survey (SF-36) were completed simultaneously by 126 Japanese patients with asthma (48 men, 78 women; 58.1 +/- 17.3 years of age), and the data were compared.
Results: Poor negative correlations (correlation coefficient (r) = -0.20 to -0.44, P < 0.05) were observed for 38 combinations of the subscales of these QOL instruments. As the severity of the patients' asthma increased, the scores of most subscales of both QOL instruments became worse. However, the AHQ-33 was more sensitive for severity than the SF-36. On logistic regression analysis, high Asthmatic Symptoms, Factors which Worsened Symptoms, Emotion, Daily Activity, and Social Activity subscale scores, as well as a high total 32-item score, of the AHQ-33 were associated with an increased risk of moderate to severe asthma. On the other hand, only the Physical functioning subscale score of the SF-36 was associated with an increased risk of moderate to severe asthma.
Conclusions: Our results show that the AHQ-33 is useful as a disease-specific QOL instrument in Japanese patients with asthma and that it is better than the SF-36, which is a generic QOL instrument. In the future, the AHQ-33 should be compared to other asthma-specific questionnaires.