Dispensing Patterns of Inhaled Asthma Medication Before and During COVID-19 Among Young Adults in the Netherlands: A Retrospective Inception Cohort Study

Abstract

Background: The impact of the coronavirus disease 2019 (COVID-19) pandemic on asthma medication trajectories, including changes in medication type or dosage, remains unclear. This study compared dispensing patterns among adults who initiated asthma inhalers before pandemic (cohorts 2014 and 2017) and during pandemic (cohort 2020). Methods: We performed retrospective inception cohort study using University of Groningen IADB.nl community pharmacy dispensing database. Individuals aged 16–44 years who initiated inhaled asthma treatment in 2014, 2017, or 2020 were followed for 2 years. Treatment steps (1–5) were based on the Global Initiative for Asthma (GINA) guideline. Primary outcomes included time to treatment step switch (step-up or step-down) and time to first oral prednisolone/prednisone, and were compared between cohorts using Cox regression models. Results: In 2014, 2017 and 2020, 1193, 960 and 730 patients initiated asthma inhalers, respectively. In all cohorts, more than half of the patients initiated treatment at the lowest step. During 2-year follow-up, fewer patients switched their treatment steps in 2020 when compared with 2014 (adjusted hazard ratio (aHR): 0.86 (95% confidence interval (CI): 0.76–0.99). From 2014 to 2020, the likelihood of treatment stepping-down decreased over time, with a 21% in 2017 (aHR: 0.79 (0.68–0.92)) and 24% in 2020 (aHR: 0.76 (0.64–0.90)) compared to 2014, while the likelihood of stepping-up did not change significantly. The risk of taking oral predniso-lone/prednisone was also significantly lower in 2020 (aHR: 0.76 (0.61–0.94)). Conclusion: During the pandemic, fewer asthma patients switched treatment steps and took oral prednisolone/prednisone. Since 2014, fewer individuals stepping down medication, with a decrease of 21% in 2017 and 24% in 2020. Possible drivers include improved adherence, better asthma control, and increased telemedicine use—trends that predate and have been accelerated by the pandemic. Research incorporating clinical data is necessary to confirm these hypotheses.