Association of Short-Acting-β-2 Agonist (SABA) Overuse and Risk of COPD among Adult Asthma Patients

Abstract

Background: Despite the well-known availability of treatment guidelines on the proper use of asthma medications, excessive SABA use and suboptimal adherence to controller medications persist.

Methods: We conducted a retrospective observational study using a linked population-based administrative claim database from the population data in British Columbia. The study included adult asthma patients aged 18 years and older during the index period from January 1, 1998 to December 31, 1999, using ICD codes and drug identification numbers. The identified patients were followed to measure COPD incidence from January 1, 2000 to December 31, 2018. The primary exposure variable "SABA overuse" was defined as the collection of more than two (2) SABA canisters in a calendar year. The standard Cox proportional hazard model was employed to examine the association.

Results: A total of 68,211 adult asthma patients with a mean age of 48.2 years, 40,455 of whom were female, met the study’s inclusion criteria based on a validated case definition. In the multivariate Cox proportional hazard model, overuse of SABA at baseline was significantly associated with increased risk of COPD compared to appropriate SABA users at the 5-year follow-up period [adjusted Hazard Ratio (aHR): 2.35, 95% CI:1.92-2.87), (aHR: 2.38, 95% CI: 2.0-2.83) at the 10-year follow-up period, and (aHR: 2.38, 95% CI: 2.03, 2.78) at the 18-year follow-up duration after controlling for all relevant covariates and confounders.

Conclusion: Interventions aimed at increasing healthcare providers’ adherence to the updated asthma clinical practice guidelines should be prioritized to minimize excess prescription of short-acting bronchodilators.