Development and validation of a questionnaire to measure asthma control

International guidelines on asthma management indicate that the primary goa l of treatment should be optimum asthma control. The aim of this study was to develop and validate the Asthma Control Questionnaire (ACQ). The authors generated a list of all symptoms used to assess control and sen t it to 100 asthma clinicians who were members of guidelines committees (18 countries). They scored each symptom for its importance in evaluating asth ma control. From the 91 responses, the five highest scoring symptoms were s elected for the ACQ. In addition, there is one question on beta(2)-agonist use and another on airway calibre (total questions=7). The ACQ was tested i n a 9-week observational study of 50 adults with symptomatic asthma, The AC Q and other measures of asthma health status were assessed at baseline, 1, 5 and 9 weeks. In patients whose asthma was stable between clinic visits, reliability of t he ACQ was high (intraclass correlation coefficient (ICC)=0.90). The questi onnaire was very responsive to change in asthma control (p<0,0001). Cross-s ectional and longitudinal validity were supported by correlations between t he ACQ and other measures of asthma health status being close to a priori p redictions. In conclusion, the Asthma Control Questionnaire has strong evaluative and d iscriminative properties and can be used with confidence to measure asthma control.