Accuracy of childhood asthma control test among Thai childhood asthma patients.

BACKGROUND: The Childhood Asthma Control Test (C-ACT) was developed to assess asthma control in children worldwide. A self-administered questionnaire for children translated into Thai language was used.

OBJECTIVE: To validate the C-ACT cut-points for evaluating the level of asthma control among Thai children, using the Global Initiative for Asthma (GINA) guideline as a gold standard.

METHODS: C-ACT score, FEV1 and assessment of level of asthma control were recorded at baseline, 3-month, 6-month, and 1-year visits among children with asthma. Receiver operating characteristic (ROC) curves was used to determine the area under the curve (AUC) of C-ACT score for determining the level of asthma control. Validity indicators were calculated at different C-ACT cut-points to determine those most appropriate for predicting controlled and uncontrolled asthma.

RESULTS: We enrolled 279 children, 64% males, with mean age 6.87±2.4 years. C-ACT score was significantly correlated with FEV1 at 3-month, 6-month, and 1-year visits (p<0.001). The AUC of C-ACT score compared with GINA score were above 80% at all visits. The suggested C-ACT score cut-point of controlled asthma was ≥ 23 (sensitivity 69.5%, specificity 73.3%, positive predictive value (PPV) 81.2%, negative predictive value (NPV) 63.8%); that of uncontrolled asthma was ≤ 18 (sensitivity 54.2%, specificity 96.9%, PPV 61.9%, NPV 95.7%).

CONCLUSIONS: The Thai version of the C-ACT is an accurate, simple, and useful tool for assessing asthma control among Thai children. The high AUC suggests that the Thai C-ACT is as good as the GINA guideline in predicting asthma control level.