Incidence, Characteristics, and Outcome of COVID-19 in Adults on Kidney Replacement Therapy: A Regionwide Registry Study

Johan De Meester; Dirk De Bacquer; Maarten Naesens; Bjorn Meijers; Marie M. Couttenye; An S. De Vriese; for the NBVN Kidney Registry Group

doi:10.1681/ASN.2020060875

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Significance Statement

In this prospective study of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in a cohort comprising all patients receiving RRT in Belgium’s Flanders region, the authors investigated whether such patients are especially vulnerable to the infection. After adjusting for age and taking into account SARS-CoV-2 under-reporting in the general population, risk of the infection did not appear to be severely increased among patients on RRT. Although mortality rates among patients on hemodialysis with SARS-CoV-2 infection were high, the authors did not find an overall excess mortality among the hemodialysis population during the epidemic wave because mortality was balanced by lower than expected mortality among patients without SARS-CoV-2 infection. These findings highlight the importance of correctly delineating the referral population and appropriately adjusting for sources of bias when reporting incidence and mortality of SARS-CoV-2 infection.

Abstract

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection disproportionally affects frail, elderly patients and those with multiple chronic comorbidities. Whether patients on RRT have an additional risk because of their specific exposure and complex immune dysregulation is controversial.

Methods To describe the incidence, characteristics, and outcomes of SARS-CoV-2 infection, we conducted a prospective, multicenter, region-wide registry study in adult patients on RRT versus the general population from March 2 to May 25, 2020. This study comprised all patients undergoing RRT in the Flanders region of Belgium, a country that has been severely affected by coronavirus disease 2019 (COVID-19).

Results At the end of the epidemic wave, crude and age-standardized cumulative incidence rates of SARS-CoV-2 infection were 5.3% versus 2.5%, respectively, among 4297 patients on hemodialysis, and 1.4% versus 1.6%, respectively, among 3293 patients with kidney transplants (compared with 0.6% in the general population). Crude and age-standardized cumulative mortality rates were 29.6% versus 19.9%, respectively, among patients on hemodialysis, and 14.0% versus 23.0%, respectively, among patients with transplants (compared with 15.3% in the general population). We found no excess mortality in the hemodialysis population when compared with mean mortality rates during the same 12-week period in 2015–2019 because COVID-19 mortality was balanced by lower than expected mortality among uninfected patients. Only 0.18% of the kidney transplant population died of SARS-CoV-2 infection.

Conclusions Mortality associated with SARS-CoV-2 infection is high in patients on RRT. Nevertheless, the epidemic’s overall effect on the RRT population remained remarkably limited in Flanders. Calculation of excess mortality and age standardization provide a more reliable picture of the mortality burden of COVID-19 among patients on RRT.

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