Quantification of asthma control: Validation of the Asthma Control Scoring System

Background: We developed an instrument for quantifying asthma control, the Asthma Control Scoring System (ACSS), based on the criteria proposed by the Canadian Asthma Consensus Guidelines. Objective: To assess the measurement properties of the ACSS. Methods: The ACSS and two other questionnaires were completed by 44 asthmatic patients on a first visit and 2 weeks later. The ACSS evaluates three types of parameters: clinical, physiologic, and inflammatory. These parameters are each quantified to obtain a maximal score of 100% and a global score is calculated as the mean of these scores. Results: The analysis showed sufficient internal consistency for every section of the ACSS (Cronbach's-α ranging from 0.72 to 0.88). Pearson's correlations indicated good test-retest reliability for the clinical score (r = 0.59, P = 0.005), the physiologic score (r = 0.86, P < 0.0001), the inflammatory score (r = 0.71, P = 0.049), and the global score (r = 0.65, P = 0.001). Cross-sectional and longitudinal construct validity were supported by moderate correlations between the ACSS scores and corresponding instruments. Conclusions: The ACSS is a valid tool for quantifying asthma control parameters, using a percent score. Further research should determine the usefulness of such an instrument as a means to improve asthma management and reduce related morbidity.