A Systematic Review and Meta-analysis of COVID-19 in Kidney Transplant Recipients

Lessons To Be Learned

Daan Kremer; Tobias T. Pieters; Marianne C. Verhaar; Stefan P. Berger; Stephan J. L. Bakker; Arjan D. van Zuilen; Jaap A. Joles; Robin W. M. Vernooij; Bas W. M. van Balkom


American Journal of Transplantation. 2021;21(12):3936-3945. 

In This Article

Abstract and Introduction


Kidney transplant recipients (KTR) may be at increased risk of adverse COVID-19 outcomes, due to prevalent comorbidities and immunosuppressed status. Given the global differences in COVID-19 policies and treatments, a robust assessment of all evidence is necessary to evaluate the clinical course of COVID-19 in KTR. Studies on mortality and acute kidney injury (AKI) in KTR in the World Health Organization COVID-19 database were systematically reviewed. We selected studies published between March 2020 and January 18th 2021, including at least five KTR with COVID-19. Random-effects meta-analyses were performed to calculate overall proportions, including 95% confidence intervals (95% CI). Subgroup analyses were performed on time of submission, geographical region, sex, age, time after transplantation, comorbidities, and treatments. We included 74 studies with 5559 KTR with COVID-19 (64.0% males, mean age 58.2 years, mean 73 months after transplantation) in total. The risk of mortality, 23% (95% CI: 21%–27%), and AKI, 50% (95% CI: 44%–56%), is high among KTR with COVID-19, regardless of sex, age and comorbidities, underlining the call to accelerate vaccination programs for KTR. Given the suboptimal reporting across the identified studies, we urge researchers to consistently report anthropometrics, kidney function at baseline and discharge, (changes in) immunosuppressive therapy, AKI, and renal outcome among KTR.


Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the associated coronavirus disease 2019 (COVID-19) have a severe impact on healthcare systems, including organ transplantation programs worldwide.[1–3] Kidney transplant recipients (KTR) with COVID-19 may be at increased risk of adverse outcomes, due to the high prevalence of comorbidities such as reduced kidney function, hypertension and diabetes and the use of immunosuppressive drugs.[4–6] As KTR are more vulnerable to infectious diseases,[6–9] it is likely that rates of mortality and AKI are higher among KTR, compared to the general population.

During the initial phase of the pandemic, knowledge regarding the treatment and outcomes of COVID-19 in KTR was mainly shared through case reports and case series. Based on these studies, several systematic reviews and meta-analyses were published that aimed to evaluate the clinical course and the effects of treatment modalities of COVID-19 in KTR.[10,11] In the past months, significantly more evidence on this topic has become available through larger studies. Having an updated overview of the risks of KTR with COVID-19 is necessary to adequately weigh the risks and benefits of kidney transplantation during the current pandemic. In addition, many international differences regarding policies and the treatment of COVID-19 in KTR exist,[12] and the described study populations are heterogeneous with regard to ethnicity, time after transplantation, and patient characteristics.[10] In this systematic review, we therefore aimed to assess all current evidence, to provide an updated and robust insight into the clinical course and outcome of COVID-19 in KTR. In addition, we aimed to review the global use of treatment modalities, and modifications in immunosuppressive regimens among KTR with COVID-19. Finally, we aimed to identify an essential set of variables with regard to baseline characteristics, treatment, and outcome measures to be reported for studies on outcome and management of KTR in any potential future epidemics.