Significance and Associated Factors of Long-Term Sequelae in Patients after Acute COVID-19 Infection in Korea

Background: As the coronavirus disease 2019 (COVID-19) pandemic has progressed, there has been a growing awareness of the long-term impacts of the COVID-19 infection. However, until recently, there was no published study that investigated COVID-19-related sequelae and related factors for greater than six months from the onset of COVID-19 symptoms or the time of COVID-19 diagnosis in Korea. Materials and Methods: Online survey and statistical analysis were conducted by Kyungpook National University Hospital on 5,252 patients diagnosed as COVID-19 between February 18, 2020 and March 14, 2020. Responders aged between 16 and 70 years were included. Longterm sequelae were defined as persistent symptoms or signs >= 6 months after acute COVID-19 infection. The survey was conducted from September 8, 2020 to September 10, 2020. Clinical characteristics and self-reported clinical sequelae of the responders were analyzed to investigate the prevalence and factors associated with sequelae using descriptive and multivariate logistic regression analysis. Results: The median period from the date of the first symptom onset or COVID-19 diagnosis to the time of the survey was 195 (interquartile range [IQR] 191 - 200) days. The response rate was 17.1% (900 out of 5,252). The median age was 31 (IQR 24.0 - 47.0) years old, and 627 responders were female (69.7%). Regarding the disease severity, 29 (3.2%) were asymptomatic, 763 (84.8%) mild, 86 (9.6%) moderate, 17 (1.9%) severe, and 5 (0.6%) critical. In total, 591 (65.7%) responders suffered from COVID-19-related long-term sequelae and 78 (8.6%) responders were receiving outpatient treatment for COVID-19-related long-term sequelae. The most common symptoms identified during the isolation period were anosmia and ageusia at 44.5% and 43.5%, respectively. Fatigue was the most common long-term sequelae, accounting for 253 (26.2%) responders, followed by concentration difficulty, amnesia, cognitive dysfunction, anxiety, and depression, which accounted for over 20%. Female gender was identified as the factor associated with mental and psychological long-term sequelae (P < 0.05). Conclusion: The results showed that the rate of COVID-19-related long-term sequelae was 65.7%. The most common long-term sequela was fatigue. The risk factor identified was female gender. It was found that the long-term sequelae had various manifestations, including mental and psychological aspects. To improve the care of COVID-19 recovered patients with COVID-19-related long-term sequelae, the participation of a comprehensive and an interdisciplinary group of researchers is required.