Post-acute sequelae of COVID-19 in cancer patients: Two cohorts in UK and Hong Kong

BackgroundLimited research exists on the risks and spectrum of complications in post-acute phase of COVID-19 in cancer patients. This study aimed to evaluate the post-acute effects of COVID-19 on different types of morbidities among cancer patients across two regions with different healthcare systems and dominant variants of COVID-19.Materials and MethodsCancer patients with COVID-19 from the UK Biobank (UKB, n = 2230; March 16, 2020 to May 31, 2021; pre-Omicron-variants dominant) and electronic medical records in Hong Kong (HK cohort, n = 22,335; April 1, 2020 to October 31, 2022; Omicron-variant dominant) were included. Each COVID-19 case was randomly matched with up to 10 non-COVID-19 cancer patients based on age and sex. Follow-up lasted until 31 August 2021 for UKB and 23 January 2023 for HK. Inverse probability treatment weighting balanced cohort characteristics. Cox regression evaluated the association of COVID-19 with morbidities occurred 30 days post-infection.ResultsCancer patients with COVID-19 consistently showed significantly higher risk of major cardiovascular diseases (CVDs) [UKB: hazard ratio [HR] 1.8 (95% CI 1.3, 2.5); HK: HR 1.4 (95% CI 1.1, 1.8)], CVD death [UKB: HR 4.3 (95% CI 2.9, 6.2); HK: HR 1.7 (95% CI 1.3, 2.4)], and all-cause mortality [UKB: HR 4.7 (95% CI 4.0, 5.5); HK: HR 1.6 (95% CI 1.5, 1.7)] in both cohorts despite the difference in dominant variants. Cancer patients at advanced ages or severely infected had higher all-cause mortality risk. However, associations between COVID-19 and CVDs became insignificant for fully vaccinated patients.ConclusionCOVID-19 infection is associated with increased risks of CVDs and mortality in cancer patients. Fully vaccination may reduce the post-acute effects of COVID-19 on CVDs. This information may guide effective pre-emptive measures to reduce COVID-19-related morbidities and mortality in cancer patients.