Predictive Properties of the Asthma Control Test and Its Component Questions for Severe Asthma Exacerbations

Abstract

Background Current U.S. guidelines recommend the Asthma Control Test (ACT) for assessing disease control and selecting treatment. Objective The goal of this study was to prospectively assess the ACT and its component questions for their utility in predicting risk of severe asthma exacerbations. Methods Individuals were participants in the Study of Asthma Phenotypes and Pharmacogenomic Interactions by Race-ethnicity (SAPPHIRE), and those included in the current analysis had the following characteristics: age ≥18 years, physician-diagnosed asthma, and longitudinal care received at a large health system in southeastern Michigan. Study participants underwent a baseline evaluation, which included answering the ACT. A severe asthma exacerbation was defined as one requiring oral steroids, an emergency department visit, or inpatient admission. Receiver-operator characteristic curves were used to measure and compare the predictive utility of the ACT and its component questions for severe asthma exacerbations. Results Of 1,180 participants, 354 (30.0%) experienced a severe asthma exacerbation within 6 months of their baseline evaluation. When compared with the individual questions that composed the ACT, the composite score was significantly better at predicting severe exacerbations with one exception; the composite ACT score and the question assessing rescue medication use were not significantly different (P=0.580). Pharmacy-based records of metered-dose inhaler short-acting beta-agonist use and asthma severity were also not significantly different from the composite ACT score. Conclusion Our study demonstrates that while the ACT is modestly predictive for exacerbations, the composite score may not be superior to assessing rescue medication use alone for predicting risk of severe asthma exacerbations.

Relationship between the Asthma Control Test (ACT) and other outcomes: a targeted literature review

“…Almost all of the 10 publications reporting on ACT score and rescue medication use [15][16][17][18][19][20][21][22][23][24] found a relationship between worsening ACT scores and increasing short-acting beta agonist (SABA) or rescue inhaler use (Table 1). Weak but statistically significant correlations between ACT score and the number of SABA inhalers dispensed were identified in two publications (ρ = − 0.33, p = 0.001 in both); these studies may have been reporting on the same population [15,16].…”

“…Ten studies reported on the relationship between improvement in ACT score and reduction in asthma exacerbations (Table 1) [17,22,23,[26][27][28][29][30][31][32].…”

“…In the other eight publications, fewer exacerbations were observed in patients with higher ACT scores [17,22,23,[28][29][30][31][32], with seven of these publications reporting a statistically significant relationship between higher ACT score and lower numbers of exacerbations in patients split into the various ACT subgroups [22,23,[28][29][30][31][32].…”

Asthma and its relationship to mitochondrial copy number: Results from the Asthma Translational Genomics Collaborative (ATGC) of the Trans-Omics for Precision Medicine (TOPMed) program

“…Average daily exposure to short acting beta agonist (SABA) medication was estimated using records of SABA fills in the 3-month period preceding study enrollment. Separate metrics of SABA use were calculated for nebulizer use and metered dose inhaler (MDI) use, as we have previously shown that both the form and the frequency of SABA medication use may be related to asthma severity [31,32]. Average daily SABA use for each participant was estimated by summing the total number of doses (e.g., 50 puffs per canister) dispensed for that individual in the 91 days preceding enrollment and dividing by 91.…”

High ACT score is not sufficient to reduce the risk of asthma exacerbations in asthma with low lung function

“…Among the five questions assessed in the ACT, there was no association between the frequency of reliever use and AEs within six months; although other four items on the ACT regarding symptom frequency and effect of asthma on daily living showed an association with exacerbations. Conversely, Cajigal et al [29] reported that rescue medication usage is the most sensitive question in predicting the risk of severe AEs within six months among patients with severe asthma, 30% of whom experienced severe AEs during the six-month study period. These studies suggest that the interpretation of individual questions in ACT for predicting the risk of AEs could be different among asthmatic patients with various severities of asthma and regional background because the usage of reliever medications could be dependent not only on their symptoms but also on individual difference in thresholds or experience.…”