Objective: This article provides evidence on the psychometric properties of the Asthma Control Questionnaire (ACQ) in adolescent and adult patients with persistent asthma treated with a combination of inhaled glucocorticoid and long-acting beta2-agonist (LABAs), and explores the factors associated with important improvements in asthma control.
Methods: Data from patients in two large (n = 737 and 772) Phase III, randomized, double-blind, parallel-group, multi-center, placebo-controlled studies of mometasone furoate/formoterol fumarate (MF/F) combination formulation compared with monotherapies in subjects with persistent asthma previously treated with either low- or medium-dose inhaled glucocorticoids were used to evaluate the ACQ psychometric properties and predictors of important ACQ improvement, defined as an ACQ score decline from baseline of 0.5 or more at the end of treatment.
Results: With 15% and 8% participation from adolescents in the low- and medium-dose studies, the ACQ yielded acceptable reliability (intraclass correlation coefficient ≥ 0.75), and baseline and change scores demonstrated moderate to strong correlations with other baseline measures and change scores in other measures of asthma-related health, including the Asthma Quality of Life Questionnaire (AQLQ12+) domains and total scores. More MF/F treatment group patients (48%) achieved an important ACQ change at 26 weeks compared with MF (32%), F (26%), and placebo (18%) treatment groups (p < .001). Use of rescue medications before randomization was a significant predictor of important ACQ improvement in both studies.
Conclusions: These findings support the psychometric properties of the ACQ to measure asthma control among persistent asthma patients and provide confidence in the significant improvements in asthma control demonstrated by the MF/F treatment group.