Introduction: The emergence of the Coronavirus Disease 2019 (COVID-19) Pandemic threatened living kidney donor transplantation services. There were concerns that kidney transplant, especially high immunological risk ABO-incompatible kidney transplants (ABOi KT) could not be performed safely due to the perceived risks of donor-transmission, early fatal post-transplant infections and utilization of hospital resources that were required for COVID-19 related care. However, data on ABOi KT performed during the COVID-19 Pandemic is scarce and there are no studies on the impact of the Pandemic on ABOi KT from South-East Asia. This study sought to compare characteristics and outcomes of ABOi KT performed before and during the COVID-19 Pandemic at an academic medical centre in Singapore.
Methods: A retrospective cohort study was performed on ABOi KT from 1st December 2009 to 31st December 2022.  Data was retrieved from the electronic medical records and stored on the encrypted transplant registry. Patients were followed-up from the date of transplant to the end of their first-year transplant anniversary. Demographic characteristics and details of desensitization were collected. Primary outcomes included patient death and graft loss while secondary outcomes included length of hospital stay, post-operative infections, delayed graft function, graft function at 1 year and important complications such as major cardiovascular events (MACE) occurring within 1 year of follow-up. Data was compared between patients who received ABOi KT before the COVID-19 Pandemic (1st December 2009 to 10th March 2020 or pre-COVID-19 era) and during the COVID-19 Pandemic (11th March 2020 to 5th May 2023 or COVID-19 era).
Results: The study population consisted of 28 ABOi KT, 19 during the pre-COVID-19 era and 9 during the COVID-19 era. There were no significant differences in baseline characteristics between the two groups and notably waiting time for transplantation was not significantly increased during the COVID-19 era. There were no significant differences in post-operative outcomes. COVID-19 infected 57.1% (n=16/28) of patients, among which 93.7% (n=15/16) were adequately vaccinated. None of these patients were admitted to the intensive care unit, died, or lost their graft from COVID-19.
Conclusion: This study demonstrated that desensitization and immunosuppression protocols for ABOi KT do not need to be modified during a Pandemic to ensure good post-transplant outcomes. Despite greater complexity and immunosuppression in ABOi KT, ABOi KT can be performed safely during the Pandemic, provided patients are adequately vaccinated and the healthcare system and process are in place to minimize the risks of COVID-19. As the world transits into an endemic COVID-19 world, the findings of this study are reassuring and do not deter the continuation of high immunological risk transplantation activities.