Territory-wide Study on Hospital Admissions for Asthma exacerbation in COVID-19 Pandemic.

RATIONALE: Asthma patients were advised to avoid Coronavirus disease 2019 (COVID-19) and comply to medication during COVID-19 pandemic. Respiratory tract infection is a common cause of asthma exacerbation. There has not been evidence suggesting the link between COVID-19 and asthma exacerbation, especially in places with dramatic responses in infection control with universal masking and aggressive social distancing.

OBJECTIVE: To assess the number for admissions of asthma exacerbation in January to April 2020 in Hong Kong with reference to admission in past five years.

METHODS: Admission records of asthma exacerbation were retrieved from Clinical Data Analysis and Reporting System. Patients with age at or above 18 years old with known history of asthma admitted for asthma exacerbation were included. Log-linear was used to model count with year and masking used as covariate, with further analysis on ambient temperature, length of hospital stays. Fisher exact test was used to compare the mortality rate and mechanical ventilation between the periods. Admissions for myocardial infarction, ischemic stroke and gastric ulcer were included as controls.

RESULTS: The number of admissions for asthma exacerbation significantly decreased by 53.2% (95%CI 50.4%-55.8%) in 2020 compared with monthly average admission in 2015-2019, with higher magnitude of decrease compared to control diagnoses. Admissions for asthma exacerbation decreased by 2.0% (95%CI 1.8%-2.2%) with every 1℃ (1.8°F) increase in temperature and by 0.8% with every 1% increase in masking (95%CI 0.8%-0.9%).

CONCLUSIONS: Hospitalization number for asthma exacerbation significantly decreased in early 2020 with similar length of stay. This was observed with concomitant practice of universal masking and social distancing during the COVID-19 pandemic in Hong Kong. We proposed that universal masking and social distancing reduced respiratory viral infection, leading to less hospital admission with asthma exacerbation.