Has Asthma Medication Use Caught Up With the Evidence?: A 12-Year Population-Based Study of Trends

Background The importance of balance between controller and reliever medications in asthma is recognized. However, to our knowledge, the extent to which real-world practice has caught up with evidence-based guidelines has not been studied. Methods This was a retrospective cohort study of individuals 15 to 67 years of age who satisfied a validated case definition of asthma in the administrative health database of British Columbia, Canada between 2002 and 2013. Each patient-year was assessed for inappropriate and excessive prescription of short-acting beta-agonists (SABAs) and the balance between controller and reliever medications. Trends on three time axes were evaluated: calendar time, time course of asthma, and age. Poisson regression was used to test for a linear trend. Results Three hundred fifty-six thousand, one hundred twelve patients (56.5% female sex; mean age, 30.5 years) contributed 2.6 million patient-years. In 7.3% of the patient-years, SABAs were prescribed inappropriately. This proportion dropped by a relative rate of 5.3% per year ( P P P Conclusions Despite overwhelming evidence regarding the risks, inappropriate prescription for SABAs was prevalent. Excessive SABA use might explain high asthma mortality in older patients. Inappropriate prescriptions declined over the study period but increased over the time course of asthma. These trends might have contributed to the declining asthma hospitalization rates in British Columbia, but there remain gaps in care and potential for improvement in asthma outcomes.