The authors reply

We agree with our colleagues¹ that the risk of death by coronavirus disease 2019 (COVID-19) integrates both (i) the risk of infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is higher in renal transplant candidates,² and (ii) the risk to develop a severe form of COVID-19, which is higher in recipients.^{2 , 3} Understanding how these distinct risks compare in each population is critical to establish appropriate guidelines.

On the basis of the data from the first wave of the pandemic, the IMPORTANT study concluded that renal transplantation should be maintained in the areas where the virus circulation is low.⁴ What strategy should be adopted in areas with intense virus circulation was less clear. A limitation of our first analysis is that candidates and recipients were considered as 2 homogeneous populations, which they are not. Due to comorbidities, 46% candidates are not active on the waiting list, which artificially increases the risk of death of candidates by considering patients that cannot be transplanted anyway. Furthermore, patients who received transplantation more than 1 year earlier represent the vast majority (92%) of the population, but they are also the patients with fewer hospital interactions and those who receive less immunosuppression. Yet if renal transplantations were maintained, it is the risk of recent transplant recipients that would count. Reanalyzing the data from the high viral risk area, we observed that recently transplanted patients had a higher risk for both SARS-Cov-2 infection (Figure 1 a) and death due to COVID-19 (Figure 1b) compared with those transplanted for more than 1 year. Furthermore, the risk of death due to COVID was the lowest for candidates active on the waiting list. Finally, overall survival over the period was higher for candidates active on the waiting list than recently transplanted patients (Figure 1c). We therefore conclude that renal transplantation should be suspended in areas with high virus circulation.

Figure 1.

Patients in the Impact of the COVID-19 Epidemic on the Mortality of Kidney Transplant Recipients and Candidates in a French Nationwide Registry study (IMPORTANT) study. The patients of the IMPORTANT study who lived in the areas with intense virus circulation during the first epidemic wave of coronavirus disease 2019 (COVID-19) were distributed into 4 groups: renal transplant candidates active (solid blue line) and inactive (dashed blue line) on the national wating list and renal transplant recipients transplanted for 1 year or less (dashed red line) or more than 1 year (solid red line). (a) Incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the 4 groups. (b) Survival of patients infected with SARS-Cov-2 in the 4 groups. (c) Global survival of the patients for the 4 groups over the study period. Log-rank tests.