COVID-19 infection and the progression of kidney disease in British Columbia, Canada.

Background: We investigated the long-term effect of COVID-19 on estimated glomerular filtration rate (eGFR) trajectory and the association with progression to kidney failure in patients with CKD.

Methods: Patients living with non-dialysis-dependent CKD from British Columbia, Canada infected with COVID-19 (cases) were matched 1:2 to non-COVID-19-infected controls on variables including pre-COVID-19 annual rate of eGFR decline. Patients were followed from 90 days from the date of COVID-19 diagnosis. The Cox proportional hazard model was used for the primary outcome of kidney failure, defined as a composite of eGFR reaching <15 ml/min/1.73 m2, initiation of maintenance dialysis or kidney transplantation. A linear mixed regression model was used to calculate the annual rate of change in eGFR.

Results: The study included 802 patients: 268 cases and 534 controls. The median age was 70 years and 54% were male. Over ≈3 years of follow-up, the risk of developing kidney failure did not differ significantly between cases and controls. The annual rate of eGFR decline was 2.05 ml/min/1.73 m2 among cases versus 1.35 ml/min/1.73 m2 among controls, representing a rate difference of 0.71 ml/min/1.73 m2 (P = .02).

Conclusion: In patients with non-dialysis-dependent CKD who survived at least 90 days without requiring dialysis, COVID-19 was not associated with an increased long-term risk of kidney failure over 3 years but was associated with a greater annual decline in eGFR. Future research with longer follow-up is required to examine if this difference persists and leads to increased risk for kidney failure.