Using the Asthma Control Test to predict severe asthma attacks


Published Online: August 18, 2016

The Asthma Control Test (ACT) questionnaire is a convenient 5-question survey used to monitor asthma control – impairment and risk. The questionnaire was initially developed to agree with expert opinion of asthma control; however, its use as a risk predictor for future asthma attacks has not been well studied.

In this original research published by The Journal of Allergy and Clinical Immunology: In Practice, Cajigal and colleagues assessed the ACT and its component questions for their ability to predict severe asthma attacks – those requiring oral steroids, an emergency room visit, or a hospital stay.  An important secondary question in this investigation was whether any one of the five ACT questions performed as well as the combined questionnaire (composite score) for predicting asthma attacks.  Study participants were from the Study for Asthma Phenotypes and Pharmacogenomic Interactions by Race-ethnicity (SAPPHIRE), a longitudinal investigation of asthma in southeastern Michigan.  The analysis was restricted to adult individuals who were at least 18 years of age and who had a physician diagnosis of asthma.

Of the 1,180 participants included in this analysis, 354 (30.0%) experienced a severe asthma attack within six months of their first study evaluation. The ACT’s ability to predict asthma attacks within six months was modest (sensitivity 43%, specificity 73%, positive predictive value 41%, and negative predictive value 75%).  However, the composite score outperformed the predictive ability of all of its component questions with one exception.  The single ACT question assessing frequency of rescue medication use (such as, albuterol) performed similarly in predicting future asthma attacks when compared with the composite ACT score.

The brevity of the 5-question ACT score encourages clinical use.  However, for the purpose of predicting future severe asthma attacks, a single question assessing rescue medication use may be just as effective.  Nevertheless, given the modest performance of both measures, additional research is needed to identify easily measurable, independent risk factors for severe asthma attacks.  

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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