Predictors of Asthma Control and Exacerbations: A Real-World Study

Abstract

Background: Achieving optimal asthma control and minimizing the risk of exacerbation are the main goals of asthma treatment.

Objective: This study aimed to assess the predictors of poor asthma control and asthma exacerbations within a population of moderate to severe asthmatic patients treated in a tertiary-care center.

Methods: We conducted a cohort study assessing 738 patients enrolled in the Quebec registry in respiratory health (RESP) with a diagnosis of asthma confirmed by a respirologist and treated in a tertiary care center from April 2010 to March 2016. Sociodemographic and clinical data, including Asthma Control Questionnaire score, were collected at enrollment in the registry (ie, cohort entry) and patients were followed for a 2-year period thereafter. The information regarding exacerbations that occurred during follow-up was collected in administrative databases (Régie d l'assurance médicale du Québec [RAMQ], Maintenance et exploitation des données pour l'étude de la clientèle hospitalière [MED-ECHO], and medication data registry [reMed]).

Results: We assessed 738 subjects (64% women). Psychological distress (odds ratio [OR] 1.91; 95% confidence interval [95% CI] 1.21-3.02), smoking (OR 3.72; 95% CI 1.72-8.05]), and poor lung function, forced expiratory volume in 1 second less than 50% (OR 4.1; 95% CI 1.48-11.34]) appeared as significant factors associated with uncontrolled asthma. Occurrence of previous asthma exacerbations (hazard ratio [HR] 6.25; 95% CI 4.01-9.75]), poor asthma control (HR 1.60; 95% CI 1.07-2.38]), forced expiratory volume in 1 second between 50% and 80% (HR 2.25; 95% CI 1.58-3.34]), and older age (HR 2.26; 95% CI 1.37-3.74]) were associated with asthma exacerbations. Adherence to asthma treatment was very low in patients with (44.4% ± 34.4%) and without asthma exacerbations (37.5% ± 33.0%).

Conclusions: Psychological distress and current smoking are modifiable factors that need to be addressed in tailored behavioral interventions to improve asthma control. Asthma exacerbations are mostly associated with the intrinsic severity of the disease.

Keywords: Asthma; Control; Exacerbation.