High mortality rate, impact of COVID-19 make AKI difficult to treat, manage
Click Here to Manage Email Alerts
Treating patients with COVID-19 at New York’s Montefiore Medical Center, nephrologist Molly Fisher, DO, noticed a high percentage of patients with the virus were starting to also experience AKI.
“The New York City area became the first large epicenter for COVID-19 in the United States in the spring of 2020,” Fisher told Nephrology News & Issues. “At that time, testing availability was limited and only the sickest patients requiring hospitalization were tested for COVID-19, resulting in an underestimation of the true magnitude of cases.
“Due to the large influx of severely ill patients with COVID-19 who simultaneously required hospitalization, we quickly saw a large number of patients with kidney injury.”
She followed up her observations with a study last year with colleagues looking at the connection between COVID-19 and AKI. They compared the incidence, risk factors and outcomes of AKI in hospitalized adults with COVID-19 (n=3,345 adults) and those without COVID-19 (n= 1,265 adults). The two groups were compared with a historical cohort of 9,859 individuals hospitalized a year earlier in the same health care system.
“Patients with AKI and COVID-19 were more likely than those without COVID-19 to require [renal replacement therapy] RRT and were less likely to recover kidney function,” the researchers said.
Those patients were also more likely to need ICU admission and mechanical ventilation and were more likely to die in the hospital. The difference in mortality rate was significant. “In the COVID-19–positive cohort, in-hospital death was 33.7% in those with AKI compared with 9.3% in those without AKI,” they said.
Worldwide issue
AKI is a syndrome of abrupt loss of kidney function, and can result from trauma, infection or other medical complications unrelated to the kidney.
“It is strongly associated with increased early and long-term patient morbidity and mortality, as well as the subsequent development of chronic kidney disease,” Philip Kam Tao Li, MD, and colleagues wrote in an article that addressed AKI as the focus of World Kidney Day.
“Mortality in patients with AKI remains high, even in the United States and other developed nations,” Anitha Vijayan, MD, professor of medicine in the division of nephrology at Washington University in St. Louis, told Nephrology News & Issues. “AKI is a disease of hospitalized patients and primarily in the ICU. High mortality reflects the severity of their underlying illness and comorbidities, but AKI is also independently associated with mortality.”
Clinical practice guidelines from Kidney Disease Improving Global Outcome define AKI as an increase in serum creatine of greater than or equal to 0.3 mg/dl (≥26.5 μmoL/L) within 48 hours; an increase in serum creatine greater than or equal to 1.5 times baseline, which is known or presumed to have occurred within the prior 7 days, or urine volume less than 0.5 mL/kg/h for 6 hours.
According to the International Society of Nephrology (ISN), an estimated 13.3 million cases of AKI are diagnosed worldwide each year, most – 11.3 million – occur in emerging countries. Of those patients with AKI, the ISN reports, 1.7 million die each year.
The ISN is in the midst of an ongoing project to develop tools aimed at preventing AKI (see sidebar).
AKI-COVID-19 connection
Researchers have been looking at various explanations as to why AKI is associated with COVID-19.
“COVID-19-associated AKI was extremely prevalent during the first surge, with an incidence ranging from 60% to 70% in critically ill patients,” Vijayan said. “The incidence of AKI has been lower in subsequent surges, for unclear reasons.
“Possible mechanisms for AKI in COVID-19 include hemodynamic alterations, early ventilation, systemic inflammatory response from the virus and less likely direct viral involvement,” she said.
Fisher added: “Volume depletion and sepsis are two common complications in patients hospitalized with COVID-19 and account for the majority of AKI in these patients. Multiple studies have identified older age, obesity, hypertension, diabetes mellitus and chronic kidney disease as risk factors for AKI.”
Few studies have looked at the long-term outcomes for patients who survive AKI and the virus, Fisher said.
“Strohbehn and colleagues performed a cohort study of 2,425 patients that evaluated AKI recovery and long-term outcomes following AKI among hospitalized patients with COVID-19 compared to influenza,” she said. “Among patients who survived to hospital discharge, the rate of AKI recovery was 56% in patients with COVID-19 compared to 70% in patients with influenza.”
It remains unclear why some patients might be more prone to developing kidney disease when they are infected with COVID-19, Alan S. Kliger, MD, a clinical professor of medicine at Yale University School of Medicine and co-chair of the American Society of Nephrology’s COVID Response Team, told Nephrology News & Issues. “I have not as yet seen any definite literature that will answer that question,” Kliger said. “What is interesting, is that the incidence of acute kidney injury requiring dialysis in previously healthy patients appears to have decreased with time. ICU COVID-19 patients on ventilators commonly had kidney failure in the first wave of the disease back in March, April and May 2020. Current ICU patients with COVID-19 seem to require dialysis less frequently.”
Kliger said data from other countries hit hard by the delta variant already show AKI is surfacing among new cases of COVID-19.
“Recent anecdotal reports from those parts of the country that have a high incidence of COVID-19 infections at this time suggest increasing numbers of patients with ICU-requiring severe illness,” Kliger said. “Of that group, there are clearly patients who have AKI and require kidney replacement therapy. I do suspect that the delta variant is responsible for more aggressive disease and more kidney injury. The data are not in yet, but that’s my speculation.”
“Unfortunately, with the combination of the highly transmissible delta variant and large percentage of the population that remains unvaccinated, COVID-19 cases are once again rising and we are seeing an increase in hospitalization rates,” Fisher said. “Since AKI is common in patients with COVID-19 who require hospitalization, I expect to see the number of AKI cases start to rise again in the coming months.
“A lot of lessons have been learned since the start of the pandemic and through these experiences,” she said. “I think that the kidney care community anticipates this and is better prepared to handle another surge.”
- Reference:
- Fisher M, et al. J Am Soc Nephrol.2020;doi:10.1681/ASN.2020040509.
- https://kdigo.org/guidelines/acute-kidney-injury/
- Li PKT, et al. Nephropathology.2013;doi:10.12860/JNP.2013.15.
- Strohbehn A, et al. Kid. Intl. Repts.2021;doi:10.1016/j.ekir.2021.07.008.
- www.theisn.org/commitment-to-kidney-health/focus-areas/acute-kidney-injury/.
- For more information:
- Molly Fisher, MD, is with the division of nephrology, department of medicine, Albert Einstein College of Medicine/Montefiore Medical Center in the Bronx, New York. She can be reached at mfisher@montefiore.org.
- Alan S. Kliger, MD, is a clinical professor of medicine, Yale University School of Medicine in New Haven, Connecticut, and is co-chair of the American Society of Nephrology’s COVID Response Team. He can be reached at alan.kliger@ynhh.org.
- Anitha Vijayan, MD, is a professor of medicine in the division of nephrology in the department of medicine at Washington University in St. Louis and is a member of the American Society of Nephrology’s COVID Response Team. She can be reached at avijayan@wustl.edu.
- Anitha Vijayan, MD, is a professor of medicine in the division of nephrology in the department of medicine at Washington University in St. Louis and is a member of the American Society of Nephrology’s COVID Response Team. She can be reached at avijayan@wustl.edu.
Collapse
Read more about
Click Here to Manage Email Alerts