Large COVID-19 Dataset: Kidney Injury in >35% of Those in Hospital

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

As a new report shows that over a third of US patients hospitalized with COVID-19 developed acute kidney injury (AKI), and nearly 15% of these patients needed dialysis, experts in the field are calling for more robust research into multiple aspects of this increasingly important issue.

Among 5449 patients admitted to 13 Northwell Health New York-based hospitals between March and April 2020, 36.6% (1993) developed AKI.

AKI was strongly linked to the occurrence of respiratory failure and was rarely a severe disease among patients who did not require ventilation — the rate of kidney injury was 89.7% among ventilated patients compared with 21.7% among other patients.

AKI in COVID-19 was also linked to a poor prognosis: 35% of those who developed AKI had died at the time of publication.

The study includes the largest defined cohort of hospitalized COVID-19 patients to date with a focus on AKI, says Jamie S. Hirsch, MD, of the Barbara Zucker School of Medicine at Hofstra/Northwell, Great Neck, New York, and colleagues in their article published online May 13 in Kidney International.

The findings track with those of a study of New York hospitals published online yesterday in the Lancet, as reported by Medscape Medical News. In that dataset, just under a third (31%) of critically ill patients developed severe kidney damage and needed dialysis.

Both of these studies help solidify the experiences of clinicians on the ground, with many US hospitals in the early phases of the pandemic underestimating the problem of AKI and having to scramble to find enough dialysis machines and dialysate solution to treat the most severely affected patients.

"We hope to learn more about the COVID-19–related AKI in the coming weeks, and that by sharing what we have learned from our patients, other doctors and their patients can benefit," said senior author of the new study, Kenar D. Jhaveri, MD. Jhaveri is associated chief of nephrology at Hofstra/Northwell.

The new report also comes as scientists from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) highlight the importance of AKI as a sequela of COVID-19 in an editorial published online May 14 in Diabetes Care.

They, too, say it is vitally important to better understand what is happening, as more and more hospitals will face COVID-19 patients with this complication.

"The natural history and heterogeneity of the kidney disease caused by COVID-19 need to be unraveled," one of the authors, Robert A. Star, MD, director of the Division of Kidney, Urologic, and Hematologic Diseases, NIDDK, told Medscape Medical News.

Such research is key because "low kidney function is an exclusion criterion in current studies" examining antiviral medications in COVID-19, he said.

"Clinical trials are needed to test therapeutic interventions to prevent or treat COVID-19–induced AKI," he added.

Extremely Ill Patients Develop AKI as Their Condition Deteriorates

Identifying risk factors for the development of AKI in COVID-19 will be critical in helping shed more light on diagnostic and predictive biomarkers, Star said.

Hirsch and colleagues say that extremely ill patients often develop kidney failure as their condition deteriorates, and this happens quickly.

Indeed, the clearest risk factors for the development of AKI were "the need for ventilator support or vasopressor drug treatment."

Other independent predictors of AKI were older age, black race, diabetes, hypertension, and cardiovascular disease.

Of those on mechanical ventilation overall in the more than 5000 patient study, almost a quarter (23.2%) developed AKI and needed renal replacement therapy, which consisted of either intermittent or continuous hemodialysis.

Star and his fellow editorialists say these numbers are important because of the knock-on effects.

"Hemodialysis in critically ill infected patients is associated with significant clotting complications and mortality as well as increased infection risk to staff," they point out.

Star told Medscape Medical News: "The incidence rate of AKI reported in this study is higher than what had been previously reported by others in the US and China and may reflect differences in population demographics, severity of illness, prevalence of comorbidities, socioeconomic factors, patient volume overwhelming hospital capacity, or other factors not yet determined."

"It may be caused by dehydration (volume depletion), heart failure, the inflammatory response to the virus (cytokine storm), respiratory failure, clotting of blood vessels (hypercoagulation), muscle tissue breakdown (rhabdomyolysis), and/or a direct viral infection of the kidney," he said.

Renal Biopsies From Patients With AKI May Help Shed Some Light

The editorialists go on to say that findings from kidney biopsies of COVID-19 patients with AKI may help shed some light on this condition.

"While difficult to perform, kidney biopsies from patients with early AKI could help us understand the underlying pathophysiologies at the cellular and molecular level and begin to target specific treatments to specific subgroups of patients," they write.

The authors note that, as part of funding opportunities provided by the National Institutes of Health for COVID-19 research, the NIDDK has published a Notice of Special Interest (NOSI) outlining the most urgent areas in need of research, with one of the focuses being on the kidney.

"As the research community emerges from the crisis situation, there should be renewed efforts for multidisciplinary research to conduct integrated basic, translational, and clinical studies aimed at greatly increasing the knowledge base to understand how both the current COVID-19 threat and future health threats affect both healthy people and people with chronic diseases and conditions," the editorials note.

The authors of the Diabetes Care editorial have reported no relevant financial relationships. Jhaveri has reported being a consultant for Astex Pharmaceuticals.

Diabetes Care. Published May 14, 2020. Editorial
Kidney Int. Published May 13, 2020. Full text

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