Even as COVID-19 was correlated with worse outcomes for people with asthma, the number of people receiving care for asthmatic episodes decreased during the pandemic, according to three studies published yesterday in Thorax.
Two focused on the United Kingdom, the first a study in England comparing general practitioner (GP) visits and hospital admissions, and the other a study on asthma-related emergency department (ED) visits and death rates in Scotland and Wales. The third was a brief communication regarding South Korea's decrease in hospital admissions for multiple respiratory diseases, including asthma.
All three observational studies used similar methods, comparing health data during the pandemic with baselines from pre-COVID. Likewise, none were designed to show causation, although the researchers suggest that behavioral changes in care-seeking or asthma management, lower air pollution due to lockdown, lower exposure to seasonal allergies, and the like may have contributed to the observed changes.
Asthma-related GP visits down in England
In the United Kingdom (with a focus on England), researchers found that asthma exacerbation incidents dropped from 46 per 100 people to 23, although no significant change occurred in related hospitalization admissions.
Data came from 670 English practices and 122 other UK locations, and the study included 100,165 patients who had at least one asthma episode from 2016 to 2020 (17.5% of all who had asthma in the Optimum Patient Care Database). Most (60.1%) were women and aged either 18 to 54 (43.7%) or 55 and above (44.2%).
From January 2016 through August 2020, 278,996 exacerbation episodes occurred, of which 82.1% were managed in primary care without needing a hospital visit. Overall, the researchers noted a significant drop in the average GP visit rate each year when comparing January to March with April to August, but they do not hypothesize why.
In 2020, GP visits dropped 0.196 episodes per person-year, but no significant change occurred in trend analysis. Still, these reductions were seen across age-groups (0.005 to 0.244 reduced episodes per person-year, particularly in ages 5 to 10), male and female sexes (0.210 to 0.277), and most regions in England (0.068 to 0.590), as well as across healthcare settings, excluding those that involved hospital admission (0.005 to 0.244).
Because of the steady number of hospital admissions, the researchers believe that mostly mild cases were reduced either because of a variety of circumstances while more severe episodes still required hospital visits.
"It's not clear whether this was an actual improvement in asthma because of reduced pollution and [fewer] opportunities for respiratory viruses to spread or whether patients were afraid of consulting primary care and stayed home," said study author Syed Shah, DPhil, MSc, in a BMJ news story. "Further research will help explain the reasons behind our findings.”
Scotland, Wales see drop in ED visits
The study based in Scotland and Wales involved a similar timeline, looking at asthma-related ED visits and deaths during the first weeks of 2020 as well as the national averages from 2015 through 2019. The researchers reported that during the pandemic the number of asthma exacerbations that resulted in ED admission dropped by 36%, but no significant change occurred in asthma deaths.
Before COVID lockdown in 2020, Scotland and Wales were starting to see reduction in ED visits already, which the researchers say could be due to an early 2019-20 flu season. When the lockdown began on Mar 23, though, a significant, instantaneous drop in the number of admissions was observed at 0.64 incidence rate ratio (IRR; 95% confidence interval [CI], 0.49 to 0.83). Scotland had an IRR of 0.59 (95% CI, 0.42 to 0.83), and Wales had an IRR of 0.70 (95% CI, 0.47 to 1.04).
Asthma-related death rates did not significantly change during the pandemic, and the researchers recorded an IRR of 0.75 for Scotland and 0.97 for Wales.
The researchers also discovered that, 1 week before lockdown in Wales, prescriptions for inhaled corticosteroid rose 121% and those for oral corticosteroids spiked 133% compared with the 5-year average. While this could be due to stockpiling, the researchers also suggest that more people may have been interested in managing their asthma better.
"Our interrupted time-series analysis has demonstrated a significant reduction in asthma admissions for the lockdown period by 36% (41% in Scotland and 30% in Wales)," the researchers write. "This finding is particularly striking given that, at the start of the pandemic, there was concern that SARS-COV-2 may act as a trigger for asthma exacerbations, in a similar manner to other respiratory viruses."
Respiratory disease decline in Korea
Researchers in South Korea, meanwhile, looked at hospitalizations due to asthma, pneumonia, influenza, and chronic obstructive pulmonary disease (COPD) during the COVID-19 pandemic. Similar to the other two studies, they found pandemic-associated decreases across all sexes and age-groups.
Compared with related hospital admissions from January 2016 through January 2020, the average cumulative incidence of asthma and COPD from February through July 2020 was 47% and 58%, respectively. Influenza had the predicted number of weekly admissions while having significantly lower incidence than the 4-year average baseline (0.22 times), and pneumonia hospitalizations decreased 53% from February through July 2020.
"The significant decrease in hospital admissions for influenza, pneumonia, COPD and asthma suggests the unintended benefits of these [COVID mitigation] measures," the researchers suggest, noting that admissions due to other acute and chronic conditions such as cancer did not have an associated decline with the pandemic.