Validity and Reliability Assessment of the Siriraj Asthma Control Questionnaire
Ratikorn Saejong MD*, Wanchai Dejsomritrutai MD**
Affiliation : * Division of Clinical Epidemiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand ** Division of Respiratory Disease and Tuberculosis, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
Objective : The present study assessed the validity and reliability of the Siriraj Asthma Control Questionnaire in Asthma
Clinic, Siriraj Hospital.
Material and Method: The data of the questionnaire responses and spirometric results from 20 randomized asthmatic
patients in the clinic including the record of 3 visits for each subject. The validation was performed by Kruskal-Wallis test
comparing the scores with the level of asthma control determined by physicians according to GINA guideline. Internal
consistency reliability was analyzed by Cronbach’s alpha.
Results : Sixty questionnaires from 20 patients with age 29-73 years were analyzed. There were 40 controlled, 7 partly
controlled and 13 uncontrolled visits. The scores from 5-items questionnaires and 6-items clinical score were significantly
associated with the physician-diagnosed groups (i.e., controlled, partly controlled and uncontrolled groups). Median scores
(min, max) were 0 (0, 5), 2 (0, 6), 4 (0, 12) respectively, (5-items, p < 0.001) and 2 (0, 7), 3 (1, 7), 6 (2,15) respectively, (6-
items, p < 0.001). Internal consistency reliability of both 5-items questionnaire and 6-items clinical score were within the
acceptable range (0.829 and 0.708 respectively). 5-items questionnaire is more associated with the physician diagnosed
group and more consistent than 6-items clinical score. Further analysis revealed cutoff point at 2.5 to separate uncontrolled
from controlled or partly controlled patient with sensitivity 76.9% and specificity 89.4% and cutoff point at 1.5 to separate
uncontrolled or partly controlled from controlled patient with sensitivity 70.0% and specificity 85.0%
Conclusion : The validity and reliability of Siriraj Asthma Control Questionnaire is acceptable and might be used in the
clinical practice and research in Thai asthmatic patients.
Keywords : Asthma, Control, Questionnaire, Thai
