Comparison of rates of AKI between two COVID-19 surges in hospitalized patients in the bronx

ABSTRACT

Background: The incidence of AKI in COVID 19 is very variable across the world. In New York City it was as high as 36% in a large series in early 2020. However, the incidence of AKI during the second surge between Oct of 2020 to early 2021 is unknown. In this study, we compared these two COVID-19 periods for the incidence of AKI amongst hospitalized patients. Methods: This was a multi-center, retrospective cohort study of patients hospitalized with COVID-19 between March 1st and July 16th 2020 (n=1,719), and between October 15th 2020 and February 28th 2021(n=997) in two NYC public hospitals, (total n= 2,716). Patients < 18 years, with End Stage Kidney Disease or a kidney transplant were excluded. Chi-squared test and Fisher's exact test were used to compare the clinical characteristics of the patients. A p-value less than 0.05 was considered statistically significant. Results: The baseline clinical characteristics and demographics of the two surges were similar. The incidence of AKI as defined by KDIGO criteria, during admission decreased from 28.7% in the first surge to 18.6% in the second surge (p<0.0001). This trend was seen both at encounter level too as shown below. For laboratory characteristics, more patients with hypernatremia and with peak CRP > 50 (Ref range <50) presented in the first surge than the second surge (p<0.0001). No differences in the peak potassium and peak D-Dimer, or ICU admission rates were seen between two surges. However, significantly more AKI patients in the first surge were on mechanical ventilation as compared to the second surge (p=0.0196). Conclusions: To our knowledge this is the first comparison reported between rates of AKI in hospitalized patients with COVID-19 during two different surge periods. The difference may be related to less severe disease during the second surge, though ICU admission rate was the same. Better care established by the time of the second surge and improved therapeutics such as early use of anti-viral agents, corticosteroids, and anticoagulation may have contributed to better outcomes. Improvement in care of COVID-19 in the second surge may have contributed to a decline in the incidence of AKI. Future studies are needed to see if this trend towards lower AKI incidence continues.