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The incidence of acute kidney injury (AKI) among patients hospitalized for COVID-19 in China was significantly lower than for similar patients in the United States, a new retrospective study from Wuhan indicates.
However, mortality among patients who do develop AKI following COVID-19 infection — especially if they require dialysis — is much higher in both regions than it is for patients who do not sustain kidney damage, this and other studies consistently show.
In an editorial accompanying the Wuhan study, published in the Clinical Journal of the American Society of Nephrology, Edward Siew, MD, Vanderbilt University Medical Center, and Bethany Birkelo, DO, Veterans Affairs, Nashville, Tennessee, say the Chinese researchers should “be commended” for their contribution to the literature. “The extraction and analysis of data under challenging conditions with several clinical and logistical unknowns are laudable,” they write.
Yet, they add, “Although the findings add important data to the existing knowledge on COVID-19–associated AKI, important knowledge gaps remain.”
“Among these are the need to better understand the factors underpinning individual differences in the risk for AKI. The incidence of AKI in this study was one fifth of that observed in more recent studies of hospitalized patients from Western countries,” they comment.
Do Age, Presence of Comorbidities Explain the Differences?
Digging down, it would appear that age and the presence of comorbidities explain a large part of the variance in AKI incidence rates.
In the group of 1392 COVID-19–infected patients admitted to a tertiary teaching hospital in Wuhan between January 18 and February 28, 2020, only 7% developed AKI during their hospital stay. That said, 72% of patients who developed AKI died in hospital.
In contrast, among hospitalized patients who did not develop AKI, the mortality rate was only 14%, note Yichun Cheng, MD, of Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China, and colleagues in their article published online September 22 in the Clinical Journal of the American Society of Nephrology.
“Acute kidney injury is a common, serious complication in critically ill patients that is associated with increased mortality, longer hospital stay, and higher medical costs,” the Chinese investigators point out.
Meanwhile, US researchers have updated a prior analysis in which the incidence of AKI was 36.6% among approximately 5500 patients admitted to 13 New York hospitals between March 1 and April 5, 2020, as reported by Medscape Medical News.
At the time of publication, 40% of these patients were still in hospital, “so we didn’t know what happened to them,” second author of the new paper, Jamie Hirsch, MD, told Medscape Medical News.
The incidence of AKI of 39.9% in the larger cohort of 9657 hospitalized patients is similar to the earlier figure. The updated analysis was published online September 19 by Jia H. Ng, MD, MSCE, of the Barbara Zucker School of Medicine at Hofstra/Northwell, Great Neck, New York City, and colleagues in the American Journal of Kidney Diseases