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 < .001). In the first year of asthma, 6.3% of patients had indicators of inappropriate SABA use, which dropped within the first 3 years but increased thereafter. Excessive prescription of SABAs increased rapidly during the time course of asthma (change of 23.3% per year; P < .001) and by age (change of 5.1% per year; P < .001).


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.
Collaboration for Outcomes Research and Evaluation, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada; Institute for Heart and Lung Health, Department of Medicine, University of British Columbia, Vancouver, Canada; Centre for Clinical Epidemiology and Evaluation, University of British Columbia, Vancouver, Canada. Electronic address: msafavi@mail.ubc.ca.
Mohsen
M
Sadatsafavi
Collaboration for Outcomes Research and Evaluation, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada; Institute for Heart and Lung Health, Department of Medicine, University of British Columbia, Vancouver, Canada.
Hamid
H
Tavakoli
Collaboration for Outcomes Research and Evaluation, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada; Centre for Health Evaluation and Outcomes Research, University of British Columbia, Vancouver, Canada.
Larry
L
Lynd
Institute for Heart and Lung Health, Department of Medicine, University of British Columbia, Vancouver, Canada; Centre for Clinical Epidemiology and Evaluation, University of British Columbia, Vancouver, Canada.
J Mark
JM
FitzGerald
D000293:Adolescent; D000318:Adrenergic beta-Agonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy*; D001955:British Columbia; D015331:Cohort Studies; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D057970:Inappropriate Prescribing / Q000639:trends*; D008297:Male; D008875:Middle Aged; D016012:Poisson Distribution; D012044:Regression Analysis; D012189:Retrospective Studies; D055815:Young Adult
D000318:Adrenergic beta-Agonists; D018927:Anti-Asthmatic Agents
asthma; asthma control; drug therapy; observational studies; short-acting beta-agonist