COVID-19-Associated Kidney Injuries Linked to Decreased eGFR

About half of all patients hospitalized with COVID-19 also have concurrent acute kidney injuries (AKI). However, it is unknown what the longitudinal effects of COVID-19 related AKI are on kidney function.

A team, led by James Nugent, MD, MPH, Section of Nephrology, Department of Pediatrics, Yale University School of Medicine, compared the rate of change in estimated glomerular filtration rate (eGFR) following hospital discharge between patients with and without COVID-19 who experienced in-hospital acute kidney injuries.

In the retrospective cohort study, the researchers examined patients who were tested for COVID-19 and developed AKI at 5 hospitals in Rhode Island and Connecticut between March 10 and August 31, 2020. To be included in the study, patients must have survived past discharge, did not require dialysis within 3 days of discharge, and had at least 1 outpatient creatinine level measurement following discharge.

The investigators assessed the link between COVID-19 associated AKI and eGFR slope after discharge using mixed-effect models and sought secondary outcomes of the time to AKI recovery for the subgroup of patients whose kidney function had not returned to the baseline level by discharge.

Overall, the study included 182 patients with COVID-19-associated AKI, as well as 1430 AKI patients not associated with COVID-19. The median age of the patient population was 69.7 years old.

Trend Lines

The researchers found results that showed trends around demographic lines. Patients with an acute kidney injury associated with COVID-19 were more likely to be African-American (n = 73; 40.1% vs. n = 225; 15.7%) or Hispanic (n = 40; 22% vs. n = 126; 8.8%).

These patients also had fewer comorbidities than those without COVID-19, but similar rates of preexisting chronic kidney disease and hypertension.

Overall, patients with COVID-19-associated acute kidney injuries had a greater decrease in eGFR in the unadjusted model (−11.3; 95% CI, –22.1 to −0.4 mL/min/1.73 m2/y; P = 0.04), as well as after adjusting for baseline comorbidities (−12.4; 95% CI, –23.7 to −1.2 mL/min/1.73 m2/y; P = 0 .03).

After fully adjusting for comorbidities, peak creatinine level, and in-hospital dialysis requirement, the investigators found the eGFR slope difference persisted (−14.0; 95% CI, –25.1 to −2.9 mL/min/1.73 m2/y; P = 0 .01).

Subgroups

For a subgroup of 319 patients who had not achieved acute kidney injury recovery by discharge, COVID-19-associated AKI was linked to decreased kidney recovery during outpatient follow-up (aHR, 0.57; 95% CI, 0.35-0.92).

“In this cohort study of US patients who experienced in-hospital AKI, COVID-19–associated AKI was associated with a greater rate of eGFR decrease after discharge compared with AKI in patients without COVID-19, independent of underlying comorbidities or AKI severity,” the authors wrote. “This eGFR trajectory may reinforce the importance of monitoring kidney function after AKI and studying interventions to limit kidney disease after COVID-19–associated AKI.”

The study, “Assessment of Acute Kidney Injury and Longitudinal Kidney Function After Hospital Discharge Among Patients With and Without COVID-19,” was published online in JAMA Network Open.