Post-acute sequelae of hospitalised COVID-19 re-infection compared with hospitalised first-time infection: a population-based retrospective cohort study in Hong Kong

Abstract

INTRODUCTION: COVID-19 infection is associated with post-acute adverse outcomes affecting multiple organ systems. Although preliminary studies have suggested that COVID-19 re-infection may have a cumulative effect on long-term outcome, differential effects of COVID-19 re-infection severe enough to be hospitalised on post-acute sequelae compared with hospitalised first-time infection have not been explored. METHODS: Retrospective cohort study using territory-wide electronic medical records databases in Hong Kong. Adults hospitalised with COVID-19 between 1 January and 30 November 2022, who survived the first 28 days after infection and was discharged, were categorised into re-infection and first-time infection groups. Individuals with reinfection were compared with those with first-time infection for all-cause mortality, all-cause hospital readmission, attendance to the emergency department and complications during the post-acute period using propensity-score-weighted Cox regression. Subgroup analyses were conducted by age (<65 and ≥65 years), sex, Charlson Comorbidity Index (0-4, ≥5), COVID-19 vaccination (0-1, 2+doses) and hospitalisation status of previous infection. RESULTS: 2244 patients with hospitalised COVID-19 re-infection and 58 894 patients with hospitalised first-time COVID-19 infection were included. After a median follow-up of 170 days, re-infection was associated with a significantly higher risk of post-acute all-cause mortality compared with first-time infection (adjusted HR (95% CI): 1.366 (1.166 to 1.600); incidence rate (95% CI): 7.3 (7.1 to 7.5) vs 4.6 (4.4 to 4.7) per 10 000 person-days), all-cause hospital readmission (1.297 (1.200 to 1.403); 50.5 (49.8 to 51.1) vs 28.1 (27.8 to 28.5)), and attendance to emergency departments (1.307 (1.199 to 1.425); 35.4 (34.8 to 35.9) vs 21.9 (21.6 to 22.2)). Findings were consistent across subgroups of age, sex, health status and vaccination status. A greater magnitude of increased risk was observed especially among those hospitalised during a previous infection. CONCLUSION: Among patients with COVID-19 infection requiring hospitalisation, COVID-19 re-infection was associated with increased post-acute mortality and morbidity compared with first-time infection. Further studies are warranted to delineate the effects on complications.

Publication DOI: https://doi.org/10.1136/bmjph-2023-000833
Divisions: College of Health & Life Sciences > Aston Pharmacy School
Funding Information: This work was supported by Collaborative Research Fund, University Grants Committee, the HKSAR Government (Principal Investigator: ICKW; Ref. No. C7154-20GF) and a research grant from the Food and Health Bureau; HMRF Research on COVID-19, The Government o
Additional Information: Copyright © Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. Published by BMJ Group.
Uncontrolled Keywords: Epidemiology,Public Health,COVID-19
Publication ISSN: 2753-4294
Data Access Statement: Data may be obtained from a third party and are not publicly available. Data are not available as the data custodians (the Hospital<br/>Authority and the Department of Health of Hong Kong SAR) have not given permission for sharing due to patient confidentiality and privacy concerns. Local academic institutions, government departments or non-governmental organisations may apply for the access to data through the Hospital Authority’s data sharing portal (https://www3.ha.org.hk/data).
Last Modified: 02 Apr 2025 07:26
Date Deposited: 31 Jan 2025 10:42
Full Text Link:
Related URLs: https://bmjpubl ... ent/3/1/e000833 (Publisher URL)
PURE Output Type: Article
Published Date: 2025-01
Published Online Date: 2025-01-20
Accepted Date: 2024-12-30
Authors: Yan, Vincent Ka Chun
Zhang, Yin
Yang, Deliang
Li, Xue
Mak, Lung Yi
Lai, Francisco T. T.
Chui, Celine S. L.
Wan, Eric Yuk Fai
Wong, Carlos
Chan, Shirley Chiu Wai
Hung, Ivan F. N.
Lau, Chak Sing
Chan, Esther Wai Yin
Wong, Ian Chi-Kei (ORCID Profile 0000-0001-8242-0014)

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