What lies beyond Asthma Control Test: Suggestions for clinical practice

Abstract

Background: Asthma Control Test (ACT ™) validity relies on Global Initiative for Asthma (GINA) definition of control. It includes neither reversibility nor inflammation assessment despite their importance as hallmark of asthma, partially unrelated to symptoms. Furthermore though rhinitis may affect the patient's perception of asthma control, its impact on ACT accuracy has not been systematically evaluated. Objective: To explore ACT validity according to a definition of control including: forced expiratory volume in 1 s (FEV1) ≥ 80%, negative reversibility test, exhaled nitric oxide at a flow rate of 50 ml/s (FeNO) < 50 ppb. Results: 177 asthmatics referring to our Unit have been studied. ACT with cut-off score ≥20 showed a good positive predictive value (83.5%) but low sensitivity (47.8%), specificity (66.7%), and negative predictive value (26.5%). ROC curves analysis indicates that ACT in patients with mild intermittent rhinitis is more reliable (AUC: 0.714; p < 0.05) than in patients with nasal polyposis/chronic rhino-sinusitis (AUC: 0.176; p > 0.05). Considering asthma classification, the probability that ACT detects patients with uncontrolled asthma is significantly higher in moderate persistent asthma subgroup than in mild persistent asthma one (OR 5.464; IC 95%: 2.5-11,9; p < 0.05). Conclusions: As ACT mainly relies on patient's reported outcomes, it may not completely reflect the airways inflammation and airways obstruction. The presence and severity of rhinitis may affect ACT outcome. The awareness of the variables that could influence ACT evaluation is much more important in the primary care setting where ACT may often represent the only tool for asthma assessment.