Jason T. Alexander

Purpose We examined the validity of the Childhood Asthma Control Test (C‐ACT) and identified recommended thresholds for uncontrolled asthma in children from varying backgrounds. Methods A systematic literature review was performed utilizing PubMed, Ovid Medline, SCOPUS, CINAHL, and conference proceedings. Studies were included if they enrolled children, had a primary outcome of asthma control, examined test validity or psychometrics, and utilized the C‐ACT. Along with study design and demographic data, we extracted all outcomes and comparisons used to validate the C‐ACT. We evaluated risk of bias using the COSMIN Risk of Bias tool. Our protocol was registered with PROSPERO (CRD42020211119). Results Of 4924 records screened, 28 studies were included. Studies were conducted internationally and published between 2007 and 2018. Average number of enrolled participants was 193 (SD = 155, range = 22–671). Ten studies calculated Cronbach's α (mean [SD] = 0.78(0.05), range = 0.677–0.83). Thirteen studies recommended cut‐offs for uncontrolled asthma (≤18–≤24). Nine studies found significant agreement or correlation between C‐ACT and Global Initiative for Asthma guidelines/physician assessment of asthma control (correlation coefficients range = 0.219–0.65). Correlation coefficients between C‐ACT and spirometry were <0.6 in five of six studies that included spirometry. Kappa values for C‐ACT and various spirometry measurements ranged 0.00–0.34. Conclusions The C‐ACT showed good internal consistency and mixed levels of agreement and correlation with various clinical asthma measures. Recommended cut‐offs for asthma control varied and had no consistent relationship with nationality, race, ethnicity, or language. Few studies examined cross‐cultural validity and multiple populations remain under‐studied.