Prescriptions for anti-asthmatic medications had an overall significant decrease during the first year of the COVID-19 pandemic, especially for bronchodilators, according to study findings published in Clinical Therapeutics.
Researchers assessed the impact of the COVID-19 pandemic on anti-asthmatic prescriptions (including anti-inflammatory drugs and bronchodilators) in primary health care and private and public hospital outpatient care in Portugal. Monthly prescription data were obtained from April 2018 to March 2021 using the System of Information and Monitoring of the Portuguese National Health Service public-access platform.
The investigators developed an interrupted time series study based on a segmented regression approach to evaluate the differences between monthly prescriptions of defined daily doses of the different drug classes. Independent variables were (1) time in months; (2) a binary variable differentiating the period before the COVID-19 pandemic (before March 2020) and during the pandemic (since March 2020), allowing for assessment of the change in the months immediately following the beginning of the COVID-19 pandemic (short-term); and (3) time since declaration of the pandemic from March 2020 to March 2021 (long-term effect). Anti-asthmatic drugs studied included inhaled beta-2-agonists, inhaled glucocorticoids, combination inhalers with beta-2-agonists and glucocorticoids, and leukotriene receptor antagonists. Notably, the investigators performed separate analyses for bronchodilators and anti-inflammatory drugs.
The prescription of anti-asthmatics, bronchodilators, and anti-inflammatory drugs in outpatient care did not significantly change with the COVID-19 pandemic in the short term after seasonal adjustment (B [non-standardized coefficient] = 2519628.786 for anti-asthmatics, B = 342665.856 for bronchodilators, and B = 2158321.227 for anti-inflammatory drugs). A significant long-term decrease was observed in prescriptions of all 3 medication groups (B = -560699.915 for anti-asthmatics, P =.004; B = -112460.851 for bronchodilators, P <.001; and B = -444541.316 for anti-inflammatory drugs, P =.007), especially with bronchodilators (β [standardized coefficient] = -1077). The decrease for anti-asthmatic prescriptions was 5 times greater than the small increase observed before the pandemic began.
We applied 2 different time series analysis methods, and observed a significant decrease in the prescriptions of anti-asthmatics during the analyzed COVID-19 pandemic period, especially concerning bronchodilators.
Prescriptions in April 2020 to March 2021 were overall lower than expected based on previous years’ patterns, according to seasonal autoregressive integrated moving average models. The monthly volume of prescriptions for anti-asthmatics was on average 18.1% lower than predicted, with 1 month having a prescription volume outside 95% confidence intervals for predicted values. The number of months is substantially different when only considering anti-inflammatory drugs for use in asthma (n = 1 month) or bronchodilators (n = 7 months).
The researchers noted that the consumption trend monitoring period should have been longer, but data could only be obtained from April 2018 onward. In addition, information for the medical conditions for which the assessed drugs were prescribed was not available, and so changes in anti-asthmatic drugs do not necessarily reflect changes in the disease. Also, only prescription data were retrieved and analyzed, and they may not reflect drug dispensing and use. Furthermore, other factors that affect anti-asthmatic drug prescription patterns cannot be excluded.
“We applied 2 different time series analysis methods, and observed a significant decrease in the prescriptions of anti-asthmatics during the analyzed COVID-19 pandemic period, especially concerning bronchodilators,” stated the study authors. “While the causes for such decrease remain elusive, our results may suggest that the COVID-19 pandemic was associated with a better control of asthma, although an overall decrease in health care seeking cannot be excluded either.”