High Rate of AKI in Hospitalized COVID-19 Patients

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More than one-fourth of patients with COVID-19 admitted to a New York City hospital in the early weeks of the pandemic had acute kidney injury (AKI), reports a study in the American Journal of Nephrology.

The retrospective analysis included 469 patients with COVID-19 admitted to the study hospital over a five-week period in March–April 2020. The hospital, which served a high-poverty area of Brooklyn, was among the centers with the most COVID-19 admissions. The study focused on the incidence of in-hospital AKI among COVID-19 patients, defined by The Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Baseline characteristics and laboratory findings associated with this diagnosis were analyzed as well.

Mortality associated with AKI among COVID-19 patients was analyzed as a secondary outcome. The study excluded patients on maintenance hemodialysis or kidney transplant recipients.

The study’s patients had a mean age of 64 years and were 57% male and 73% African American. About 15% of patients were in a hemodynamically unstable condition at presentation, and 21% received mechanical ventilation during their hospital stay.

At admission, 44.1% of the patients had an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73 m2. During hospitalization, 27.1% of COVID-19 patients developed AKI; this included 39.1% of patients with a low eGFR compared to 17.9% of those with an eGFR of 60 mL/min/1.73 m2 or higher. Stage 3 AKI was present in about one-half of the cases.

Patients with low eGFR were more likely to develop AKI within 48 hours after admission: 53.1% versus 23.4%. Risk factors for AKI included male sex; hypertension; angiotensin-converting enzyme inhibitor or nonsteroidal anti-inflammatory drug use; hemodynamic instability; mechanical ventilation; acute respiratory distress syndrome; and elevated ferritin, creatinine kinase, brain natriuretic peptide, and troponin 1 levels.

Mortality was 71.1% among patients with AKI versus 28.45% in those without AKI. On adjusted analysis, independent risk factors for death were elevated blood urea nitrogen, hazard ratio (HR) 1.75; low eGFR, HR 1.43; AKI stage 2, HR 1.86; and AKI stage 3, HR 2.1. For patients with stage 3 AKI, kidney replacement therapy did not improve survival.

As has become clear, COVID-19 is associated with a significant risk of AKI in hospitalized patients. These data from early in the pandemic show a high incidence of AKI at a hospital serving a low-income, racial/ethnic minority population in New York.

The experience shows “extremely high” mortality, particularly in patients with stage 3 AKI [Zahid U, et al. Acute kidney injury in COVID-19 patients: An inner city hospital experience and policy implications. Am J Nephrol 2020; 51:786–796. doi: 10.1159/000511160].