COVID-19 and Kidney Health

Few people are aware of the potential effect of COVID-19 on their kidney health. What to know about this pathophysiology.

With the National Kidney Foundation and C. John Sperati MD, MHS

SARS-CoV-2 directly infects kidney cells, and as such, the kidney may be a direct target of the virus.

As more and more information unfolds about how the Coronavirus, or SARS-CoV-2, can affect the body, experts are discovering that it can have a severe and lasting impact on other organs, including the heart and the kidneys.

While physicians may be up to date on these developments, a new poll, commissioned by the National Kidney Foundation and Harris, suggests that your patients are not aware of the associations and the dangers.

Meanwhile, research is accumulating about a distinct pathophysiology of acute kidney injury in COVID-19 and exactly how devastating it can be.

Survey Findings

The online survey, conducted May 1-3, 2020, included a nationally representative sample of 2,039 U.S. adults. Among the findings:

  • 17% are aware that acute kidney injury could be a result of COVID-19
  • 19% of women, but just 14% of men, are aware of this association
  • Older Americans are twice as likely to know as younger Americans
  • Less than half of respondents are aware that COVID-19 will likely lead to a higher number of Americans with either chronic kidney disease, kidney failure, or both
  • 58% are aware of the acute respiratory failure that can occur with COVID-19
  • 54% are aware of the pneumonia linked with COVID-19
  • 52% are aware that acute respiratory distress syndrome (ARDS) is associated with COVID-19

Emerging Research on COVID-19 and Kidney Health

C. John Sperati, MD, MHS, an adult nephrologist at Johns Hopkins and director of the Nephrology Fellowship Training Program there, reviewed the survey findings for Endocrine Web. "I'm actually surprised as many as 17% of respondents indicated they were aware of acute kidney injury as a result of COVID-19," he says. "I would have expected the number to be even lower."

He notes that "the kidney implications of COVID-19 are slowly growing in recognition among healthcare providers. It's been a slow process in the medical community, so it is not surprising that it would be slow in the general public."

Another surprise, he says, is that such a relatively low percent were aware of the severe respiratory features of the disease, especially since COVID-19 is in the news constantly.

The literature on COVID-19 and acute kidney injury has varied widely, Dr. Sperati says. "Some early reports suggested it wasn't a major issue, but it has become clear, especially in hard-hit areas of the United States, that AKI may develop in upwards of 30% of hospitalized patients." And, he says, AKI is common in critically ill patients. "We know SARS-CoV-2 directly infects kidney cells, and as such, the kidney may be a direct target of the virus."

Recent Studies

In one study, researchers from the Northwell COVID-19 Research Consortium and the Northwell Nephrology COVID-19 Research Consortium evaluated 5,449 patients admitted to 13 academic and community hospitals in metro New York between March 1 and April 5, 2020. After excluding those with end-state kidney disease or a kidney transplant, AKI developed in 36.6% or 1,993. Of these, 14.3% needed renal replacement therapy (RRT).

Patients in the hospital with COVID-19, especially those in the ICU, are at risk for AKI, affecting up to 30%, according to a team of researchers from Northwestern University Feinberg School of Medicine. The researchers reviewed two different studies from China that had autopsy information about kidney tissues from patients who died from COVID-19.

The researchers say that the kind of AKI found in COVID-19 patients is complex and involves factors not usually seen in other patients with AKI who need the ICU. The virus may invade the kidneys, the Northwestern researchers say, among other factors at play.

Another team of researchers performed a prospective cohort study of 701 patients with COVID-19 admitted to a tertiary teaching hospital that also encompassed three affiliated facilities following the major outbreak in Wuhan in 2020. During the study period, AKI occurred in 5.1% of patients.

The researchers performed a Kaplan-Meier analysis and demonstrated that those with kidney disease had a significantly higher risk of in-hospital death, and the risk varied widely depending on the independent risk factors (AKI stage 2, for instance, had a HR of 3.51).

These researchers conclude: "Thus, our findings show the prevalence of kidney disease on admission and the development of AKI during hospitalization in patients with COVID-19 is high and is associated with in-hospital mortality. Hence, clinicians should increase their awareness of kidney disease in patients with severe COVID-19."

Take-Home Points for Endocrinologists and PCPs

The risk for AKI is greatest in those with COVID-19 sick enough to be hospitalized, Dr. Sperati points out. As many endocrinologists and PCPs may practice mostly in the outpatient environment, ''Their first contact with COVID-19 related AKI will be in patients returning to the office for follow-up after hospital discharge."

His advice for them: "It's important to remember that the majority of patients with COVID-19 will recover fine. A subset, however, will have severe disease." Those at risk for severe disease, of course, are older, obese with significant comorbidities, or of African-American or Hispanic descent. Physicians should be especially mindful of the risk for AKI in these patients, Dr. Sperati tells Endocrine Web.

The best take-away for physicians from the poll and the research, according to the National Kidney Foundation, is this: "Endocrinologists and PCPs should know that during follow-ups after recovery from COVID-19 they should ask about any history of AKI during the course of the illness, and to check for kidney disease even if patients did not experience AKI. There's still so much that's unknown about COVID-19, that it is possible the kidneys could have been impacted in ways other than AKI. This is of particular importance for patients who have diabetes, which already puts them at increased risk for kidney disease even without the potential added risk of having had COVID-19."

Can the kidneys recover after COVID-19? According to Dr. Sperati, it is as yet uncertain how many people with COVID-19-related kidney damage regain function.  Those who do not require dialysis will have better outcomes than those who do. And there is hope, he adds. "We have seen patients at Johns Hopkins who recover kidney function." Even so, he still calls the need for dialysis "a worrisome development in patients with COVID-19."

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