Physicians caring for COVID-19 survivors should routinely check kidney function, which is often damaged by the SARS-CoV-2 virus months after both severe and milder cases, new research indicates.
The largest study to date with the longest follow-up of COVID-19-related kidney outcomes also found that every type of kidney problem, including end-stage kidney disease (ESKD), was far more common in COVID-19 survivors who were admitted to the ICU or experienced acute kidney injury (AKI) while hospitalized.
Researchers analyzed U.S. Veterans Health Administration data from more than 1.7 million patients, including more than 89,000 who tested positive for COVID-19, for the study, which was published online Sept. 1, 2021, in the Journal of the American Society of Nephrology.
The risk of kidney problems “is more robust or pronounced in people who have had severe infection, but present in even asymptomatic and mild disease, which shouldn’t be discounted. Those people represent the majority of those with COVID-19,” said senior author Ziyad Al-Aly, MD, of the Veteran Affairs St. Louis Health Care System.
“That’s why the results are important, because even in people with mild disease to start with, the risk of kidney problems is not trivial,” he told this news organization. “It’s smaller than in people who were in the ICU, but it’s not ... zero.”
Experts aren’t yet certain how COVID-19 can damage the kidneys, hypothesizing that several factors may be at play. The virus may directly infect kidney cells rich in ACE2 receptors, which are key to infection, said nephrologist F. Perry Wilson, MD, of Yale University, New Haven, Conn., and a member of Medscape’s advisory board.
Kidneys might also be particularly vulnerable to the inflammatory cascade or blood clotting often seen in COVID-19, Dr. Al-Aly and Wilson both suggested.
COVID-19 survivors more likely to have kidney damage than controls
“A lot of health systems either have or are establishing post-COVID care clinics, which we think should definitely incorporate a kidney component,” Dr. Al-Aly advised. “They should check patients’ blood and urine for kidney problems.”
This is particularly important because “kidney problems, for the most part, are painless and silent,” he added.
“Realizing 2 years down the road that someone has ESKD, where they need dialysis or a kidney transplant, is what we don’t want. We don’t want this to be unrecognized, uncared for, unattended to,” he said.
Dr. Al-Aly and colleagues evaluated VA health system records, including data from 89,216 patients who tested positive for COVID-19 between March 2020 and March 2021, as well as 1.7 million controls who did not have COVID-19. Over a median follow-up of about 5.5 months, participants’ estimated glomerular filtration rate and serum creatinine levels were tracked to assess kidney health and outcomes according to infection severity.
Results were striking, with COVID-19 survivors about one-third more likely than controls to have kidney damage or significant declines in kidney function between 1 and 6 months after infection. More than 4,700 COVID-19 survivors had lost at least 30% of their kidney function within a year, and these patients were 25% more likely to reach that level of decline than controls.
Additionally, COVID-19 survivors were nearly twice as likely to experience AKI and almost three times as likely to be diagnosed with ESKD as controls.