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Evaluation of the asthma control test: A reliable determinant of disease stability and a predictor of future exacerbations
Author(s) -
KO FANNY W.S.,
HUI DAVID S.C.,
LEUNG TINGFAN,
CHU HONGYIN,
WONG GARY W.K.,
TUNG ALVIN H.M.,
NGAI JENNY C.N.,
NG SUSANNA S.S.,
LAI CHRISTOPHER K.W.
Publication year - 2012
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/j.1440-1843.2011.02105.x
Subject(s) - medicine , exhaled nitric oxide , asthma , spirometry , guideline , confidence interval , odds ratio , physical therapy , pediatrics , pathology
Background and objective: This study assessed the asthma control test (ACT) cut‐off values for asthma control according to the Global Initiative for Asthma guideline in adults and the effectiveness of ACT scores in predicting exacerbations and serial changes in ACT scores over time in relation to treatment decisions. Methods: Subjects completed ACT together with same‐day spirometry and fractional concentration of exhaled nitric oxide (FeNO) measurement at baseline and at 3 months. Physicians, blinded to the ACT scores and FeNO values, assessed the patient's asthma control in the past month and adjusted the asthma medications according to management guidelines. Asthma exacerbations and urgent health‐care utilization (HCU) at 6 months were recorded. Results: Three hundred seventy‐nine (120 men) asthmatics completed the study. The ACT cut‐off for uncontrolled and partly controlled asthma were ≤19 (sensitivity 0.74, specificity 0.67, % correctly classified 69.5) and ≤22, respectively (sensitivity 0.73, specificity 0.71, % correctly classified 72.1). Baseline ACT score had an odds ratio of 2.34 (95% confidence interval: 1.48–3.69) and 2.66 (1.70–4.18) for urgent HCU and exacerbations, respectively, at 6 months ( P < 0.0001). However, baseline FeNO and spirometry values had no association with urgent HCU and exacerbations. The 3‐month ACT score of ≤20 correlated best with step‐up of asthma medications (sensitivity 0.65, specificity 0.81, % correctly classified 72.8). For serial changes of ACT scores over 3 months, the cut‐off value was best at ≤3 for treatment decisions with low sensitivity (0.23) and % correctly classified (57.3%) values. Conclusions: Single measurement of ACT is useful for assessing asthma control, prediction of exacerbation and changes in treatment decisions.