Trends in prescriptions and costs of inhaled medications in chronic obstructive pulmonary disease: a 19-year population-based study from Canada

Abstract

Background

The patterns of medication use in chronic obstructive pulmonary disease (COPD) may change over time due to the availability of new medications, updates in guideline-based recommendations, and changes in patient and care provider preferences.

Objectives

To document population-level trends of filled prescriptions and costs for major classes of inhaled COPD therapies.

Method

We used administrative health databases of the province of British Columbia, Canada, from 1997 to 2015, to create a retrospective cohort of COPD patients. We documented the percentage of patients receiving major inhaled COPD-related medications, including short-acting beta-2 adrenoreceptor agonists (SABA), long-acting beta-2 adrenoreceptor agonists (LABA), inhaled corticosteroids (ICS), short-acting muscarinic receptor antagonists (SAMA), and long-acting muscarinic receptor antagonists (LAMA). We quantified the average, and relative annual change in, dispensed quantities and costs (in 2015 Canadian dollars [$]) of medications. Combination therapy was assessed as the proportion of time covered by two or more long-acting medications of different classes.

Results

A total of 176,338 patients were included in the final cohort (mean age at entry 68.7, 48.5% female). In 2015, the most common medication was ICS (45.7% of the patients), followed by LABA (36.5%). LAMA was the least used medication (18.9%). The number of filled prescriptions per patient per year for LAMA (+7.8% per year) and LABA (+4.9%) increased, while they decreased for SAMA (−6.3%) and SABA (−3.8%), and remained relatively constant for ICS. The average annual per-patient costs of inhaled medications were $570.8 in 2015, which was double the costs from 1997. Single-inhaler ICS/LABA had the highest rate of increase (11.6% per year), and comprised 53.7% of the total costs of inhalers in 2015. In 2015, 28.5% of the patient time was on combination therapies, with 7.1% on triple ICS/LABA/LAMA therapy.

Conclusion

Utilization of inhaled therapies for COPD has changed significantly over time. The low utilization of LAMA and high utilization of combination therapies (particularly those containing ICS) do not seem to be aligned with COPD treatment guidelines.

Keywords:

• COPD
• medication
• cost
• trend
• SABA
• ICS
• LABA
• LAMA
• SAMA

Author contributions

MS, JMF, and DS formulated the study idea. MS and DS designed the study. AG, TK, and KJ provided significant input in the study design and analysis plan. HT performed the data analyses and wrote the first draft of the manuscript with KJ. All authors contributed to interpretation of findings, critically commented on the manuscript and approved the final version to be published, and agree to be accountable for all aspects of the work. MS is the guarantor of the manuscript.

Disclosure

This study was funded by the Canadian Respiratory Research Network (CRRN). CRRN is supported by grants from the Canadian Institutes of Health Research (CIHR)-Institute of Circulatory and Respiratory Health, Canadian Lung Association (CLA)/Canadian Thoracic Society (CTS), British Columbia Lung Association, and Industry Partners Boehringer-Ingelheim Canada Ltd, AstraZeneca Canada Inc., and Novartis Canada Ltd. Funding for the training of postdoctoral students and new investigators within the network was supported by the above funding Sponsors and as well by GlaxoSmithKline Inc. Dr Sadatsafavi receives salary support from the Michael Smith Foundation for Health Research and the Canadian Institutes of Health Research and reports personal fees from GSK and grants from AstraZeneca Canada, outside the submitted work. None of the authors have declared any other actual or perceived conflicts of interest in this work.