Medication use and indicators of poor asthma control in patients with and without allergies

Background: Approximately two-thirds of people with asthma have some evidence of allergy; their condition differs from nonallergic asthma in terms of predominant symptoms and clinical outcomes. Objective: To compare asthma control and medication use among patients with persistent asthma with evidence of allergy (PA-EA) and patients with persistent asthma with no evidence of allergy (PA-NEA). Methods: A retrospective analysis of survey responses and medication claims data from the Observational Study of Asthma Control and Outcomes study, a prospective survey linked to retrospective claims-based analysis of patients ages ≥ 12 years with persistent asthma in a U.S. health maintenance organization. Evidence of allergy was defined as both a positive response to a survey question about hay fever and/or seasonal allergies and one or more medical diagnostic codes for atopic conditions. Regression models were used to compare asthma control (Asthma Control Questionnaire [ACQ] scores) and asthma medication use between PA-EA and PA-NEA. Results: Adjusted data showed that, versus the patients with PA-NEA (n = 312), patients with PA-EA (n = 971) had higher (worse) 5-item and 6-item ACQ (ACQ-5 and ACQ-6) scores (by 0.34 [95% confidence interval {CI}, 0.24-0.44]; and 0.31 [95% CI, 0.21- 0.40], respectively), were more likely to have poorly controlled asthma (ACQ-5 score ≥ 1.5: Odds ratio 3.37 [95% CI, 2.07-5.50]; ACQ-6 score ≥ 1.5: Odds ratio 3.46 [95% CI, 2.13-5.62]) and less likely to have well-controlled asthma (ACQ-5 score ≤ 0.75: Odds ratio 0.21 [95% CI, 0.13- 0.34]; ACQ-6 score ≤ 0.75: Odds ratio 0.21 [95% CI, 0.13- 0.35]). Patients with PA-EA also had greater asthma medication use, most notably 2.5 times more prescriptions of high-dose inhaled corticosteroid in a 4-month period (95% CI, 1.21-5.16) and 16.15 times higher odds of chronic oral corticosteroid use (95% CI, 1.50 -174.09) versus PA-NEA. Conclusion: The patients with PA-EA versus PA-NEA had worse asthma control and greater medication use. These patients may need more vigilant clinical oversight and treatment management to ensure adequate asthma control.