Background: The impact of Covid-19 and ensuing national lockdown on asthma exacerbations is unclear.
Methods: We conducted an interrupted time-series (lockdown on 23rd March as point of interruption) analysis in asthma cohort identified using a validated algorithm from a national-level primary care database, the Optimum Patient Care Database (OPCRD). We derived asthma exacerbation rates for every week and compared exacerbation rates in the period: January-August 2020 with a pre-Covid-19 period; January-August 2016-2019). Exacerbations were defined as asthma-related hospital attendance/admission (including accident and emergency visit), or an acute course of oral corticosteroids with evidence of respiratory review, as recorded in primary care. We used a generalised least squares modelling approach and stratified the analyses by age, sex, English region, and healthcare setting.
Results: From a database of 9,949,487 patients, there were 100,165 asthma patients who experienced at least one exacerbation during 2016-2020. Of 278,996 exacerbation episodes, 49,938 (17.1%) required hospital visit. Comparing pre-lockdown to post-lockdown period, we observed a statistically significant reduction in the level (-0.196 episodes per person-year; p-value<0.001; almost 20 episodes for every 100 asthma patients per year) of exacerbation rates across all patients. The reductions in level in stratified analyses were: 0.005-0.244 (healthcare setting, only those without hospital attendance/admission were significant), 0.210-0.277 (sex), 0.159-0.367 (age), 0.068-0.371 (region).
Conclusions: There has been a significant reduction in attendance to primary care for asthma exacerbations during the pandemic. This reduction was observed in all age groups, both sexes, and across most regions in England.