The Impact of Coronavirus Disease 2019 (COVID-19) on Lung Function, Exercise Capacity and Quality of Life in a Cohort of Survivors

Background: The lung function outcome among COVID-19 survivors in Hong Kong remained unknown. Methods: Patients above the age of 18 years old with the principal diagnosis of COVID-19 who were discharged from a tertiary center in Hong Kong between the period of 1st February 2020 to 31st July 2020 were offered three lung function tests at approximately one, three and six months upon discharge for monitoring of their outcome. Six-minute walk test (6MWT) and health related quality of life assessment by Medical Outcomes Study 36-item Short Form General Health Survey (SF-36) were arranged on the same day of lung function test. Results: Thirty patients had lung function test performed within 60 days after discharge. Nineteen and twelve patients had lung function test performed at 60-180 days and 180 days after discharge respectively. After corrected for underlying lung diseases, 32% patients have reduced hemoglobin adjusted DLCO and PImax, while 88% patients have reduced PEmax. For patients with serial lung function performed, adjusted DLCO and PImax improved with time. The exercise capacity of COVID-19 survivors was significantly lower than normal subjects in most age groups. COVID-19 survivors have lower quality of life in the context of physical functioning, social functioning and role limitation due to physical problems, compared with normal subjects. Conclusion: COVID-19 leads to lung function abnormalities including reduced diffusing capacity of carbon monoxide, maximal inspiratory pressure and maximal expiratory pressure in more than 40% of patients, which improved with time. Exercise capacity and health status of COVID-19 survivors are lower than normal subjects.