Background.The gold standard in classifying severity of asthma is the GINA classification, however, the numeric
cut-off values of frequency and intensity symptoms and parameters of physiologic dysfunction used to classify asthma
severity are artificial and transitory. Currently, asthma questionnaires, such as the Asthma Control Test (ACT), provides
a more simplified assessment of control by not requiring FEV1. It is the aim of this study to compare the Asthma Control Test (ACT) and GINA classification, including FEV1, in assessing asthma severity and validate ACT as a screening tool for asthma severity.
Methods. This is a prospective cohort study involving adult asthmatic patients who were classified based on their ACT scores into controlled asthma (ACT>19) and uncontrolled asthma (ACT < 19). They were then classified accordingly to their GINA asthma symptom severity. After which, FEV1 and peak expiratory flow rate (PEFR) were recorded. Correlation as well as measures of validity were obtained, with level of significance set at 0.05.
Results. Among the 86 patients included in this study, 62 have ACT scores < 20. The prevalence rate of uncontrolled asthmatics was 72% with majority classified as moderate persistent. Significant association between ACT and GINA classification (p-value 0.00), ACT and FEV1 in liter (p-value 0.013), ACT and FEV1 as % predicted (p-value 0.023) and ACT and PEFR in % predicted (p-value 0.037) were observed. There appeared to be an association between a lower ACT score and a more severe symptom severity. ACT was 92.3% sensitive and 90.5% specific with AUC of 0.972. The positive predictive value was 98% and the negative predictive value is 79%.
Conclusion. With its high sensitivity, specificity and positive predictive value, ACT can served as an alternative
diagnostic tool in assessing asthma severity even without an aid of a spirometer or a peak flow meter. An ACT score of at least 20 can classify patient as intermittent or' controlled asthmatic while an ACT score < 20 can classify the patient as in persistent or uncontrolled asthmatics.