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

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.

Keywords: COVID-19; clinical epidemiology; hemodialysis; kidney transplantation; mortality; virology.

Graphical abstract

Figure 1.

Cumulative incidence of SARS-CoV-2 infection. Cumulative incidence of SARS-CoV-2 infection in the adult general population (gray bars, y axis left), adult patients on hemodialysis (blue line, y axis right), and adult kidney transplant recipients (red line, y axis right) in the Flemish region from March 2 to May 25, 2020. Implementation of general lockdown (yellow star, March 14), start of routine screening of all nursing home inhabitants (blue triangle, April 8), initial phase of the exit strategy with reopening of commercial activity (purple bar, May 11), and partial reopening of schools and resumption of daily life and gatherings (red crescent, May 18) are shown. Patients on peritoneal dialysis are not shown.

Figure 2.

All-cause mortality in adult patients on hemodialysis. Periodic all-cause mortality stratified by age group in adult patients on hemodialysis, expressed as percentage of total number of patients on hemodialysis at risk. Mortality in patients with (orange bars) and without (red bars) diagnosis of SARS-CoV-2 infection during the study period (March 2 to May 25; week 10 to week 21) in 2020 was compared with mortality during the same period in 2015–2019 (gray bars).

Figure 3.

Excess all-cause mortality in adult patients on hemodialysis. All-cause mortality, expressed as percentage of deaths per week from week 1 to week 21, in adult patients on hemodialysis without (red bars) and with (orange bars) diagnosis of SARS-CoV-2 infection in 2020 compared with the mean and 95% confidence limits (blue line and dotted blue lines, respectively) for that week during the period 2015–2019.

Figure 4.

Excess all-cause mortality in the adult general population. All-cause mortality, expressed as absolute number of deaths per week from week 1 to week 21, in the adult general population without (green bars) and with (orange bars) diagnosis of SARS-CoV-2 infection in 2020 compared with the mean and 95% confidence limits (blue line and dotted blue lines, respectively) of the period 2015–2019.