Health Services Utilization Is Increased in Poor Perceivers of Bronchoconstriction and Hyperinflation in Asthma

Abstract

Impaired symptom perception is often listed as a risk factor for life-threatening asthma, but there is limited evidence to support this. We aimed to determine whether impaired perception of bronchoconstriction (BC) and/or dynamic hyperinflation (DH) are risk factors for severe asthma exacerbations. In this prospective cohort study, individuals with asthma underwent high-dose methacholine challenge testing. Changes in forced expiratory volume in 1 second (FEV1) (% predicted) and inspiratory capacity (IC) (% predicted) were measured to assess the degree of BC and DH, respectively, during high-dose methacholine bronchoprovocation. Participants rated dyspnea intensity during testing and were categorized as poor, normal, and over perceivers of BC and DH based on perception scores at standardized changes (20%, 30%, and 40%) in FEV1 (% predicted) and IC (% predicted). We compared the rates of severe asthma exacerbations (defined as one of emergency department [ED] visit or hospitalization) between groups, using Ontario's administrative health databases. Poor perceivers had higher rates of ED visits and hospitalizations as compared with normal perceivers at 4 of 6 threshold decreases in FEV1 and IC studied. Poor perceivers of severe DH had a 6-fold increase in asthma exacerbations (odds ratio, 5.7; 95% confidence interval, 1.31-25.03). Health services utilization is increased in individuals with asthma who have poor perception of BC andDH. Poor perceivers of severe DH appear to be at the highest risk of exacerbations.