Validity of Asthma Control Test in Chinese patients

So far, in China, there has been no effective or easy procedure to define the control of asthma. This study assesses the validity of Asthma Control Test in Chinese patients. Three questionnaires (Asthma Control Test, Asthma Control Questionnaire and the 30 second asthma test) were administered to 305 asthma patients from 10 teaching hospitals across China. Spirometry was also used. Asthma specialists rated the control of asthma according to patients' symptoms, medications and forced expiratory volume in first second. The patients were divided into noncontrolled group and controlled group according to the specialists' rating. Reliability, empirical validity and screening accuracy were conducted for Asthma Control Test scores. Screening accuracy was compared among 3 questionnaires. The patients' self rating and the specialists' rating were also compared. The internal consistency reliability of the 5-item Asthma Control Test was 0.854. The correlation coefficient between Asthma Control Test and the specialists' rating was 0.729, which was higher than other instruments. Asthma Control Test scores discriminated between groups of patients differing in the percent predicted forced expiratory volume in first second (F = 26.06, P < 0.0001), the specialists' rating of asthma control (F = 88.24, P < 0.0001) and the Asthma Control Questionnaire scores (F = 250.57, P < 0.0001). Asthma Control Test showed no significant difference with Asthma Control Questionnaire in the percent correctly classified, while the percent correctly classified by Asthma Control Test was much higher than 30 second asthma test. The patients' self rating was the same as assessment of the specialists (t = 0.65, P = 0.516). The Asthma Control Test is an effective and practicable method for assessing asthma control in China.