A systematic review and meta-analysis of COVID-19 in kidney transplant recipients: Lessons to be learned

Abstract

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.

Keywords: clinical research/practice; complication: infectious; immunosuppressive regimens; infection and infectious agents - viral; infectious disease; kidney transplantation/nephrology; meta-analysis; translational research/science.

FIGURE 1

PRISMA study selection flow. AKI, acute kidney injury; KTR, kidney transplant recipients

FIGURE 2

Reported outcomes of KTR with COVID-19. Overall reported mortality of hospitalized KTR with COVID-19 (A) is 23% and appears higher in the first period. AKI (B) occurs in 50% of the cases and appears to be increased in the period after July 2020

FIGURE 3

Reported outcomes of KTR with COVID-19 among age groups. Overall reported mortality of hospitalized KTR with COVID-19 (A) is 17% in studies with a mean age lower than 50 years, 23% in the age group 50–60 years, and 27% in studies reporting on age groups older than 60 years. Occurrence of AKI (B) was lowest in the youngest age group (41%) and highest in the oldest groups (54%)

FIGURE 4

Effect of time between transplantation and COVID-19 diagnosis on outcome. KTR who received their kidney 15 months or less before COVID-19 diagnosis appeared to have a (A) higher mortality risk compared to patients who received their kidney 16–60 or more than 60 months before COVID-19 diagnosis, whereas the occurrence of (B) AKI was similar in all groups