Predictors of recovery of kidney function following AKI during hospitalization for COVID-19

Background: Studies have shown that COVID-19 hospitalization is associated with severe AKI. However, determinants of kidney function recovery for these patients are not well studied. Methods: We conducted a retrospective analysis of patients admitted to our institution from March 2020 to April 2021 with diagnoses of COVID-19 and AKI. Recovery of kidney function was defined as a discharge creatinine less than 0.3 mg/dL above baseline. Data on patients' demographics, comorbidities, AKI stage, ICU admission, and laboratory values were collected by chart review. Univariate analysis and a multivariate logistic regression model were used to identify factors associated with kidney recovery. Results: Of 216 patients, the average age was 66.3 years and 56.0% were men. 62% of patients had recovery of kidney function by discharge. Univariate analysis identified congestive heart failure (CHF, p = 0.063), AKI-D (p < 0.001), AKI stage (p < 0.001), ICU admission (p < 0.001), and lower albumin (p = 0.040) as correlates of nonrecovery at discharge. In the multivariate logistic regression model [(AUC: 0.732, 95% CI (0.664-0.800)], CHF (p = 0.010), AKI-2 (p = 0.011), AKI-3 (p = 0.001), and ICU admission (p = 0.006) remained associated with non-recovery (Table 1). Follow-up data, at a median of 64 days post-discharge, was available for 61% of the cohort (n = 131). Of these patients, 14% had new recovery after discharge, while 18% had no improvement compared to discharge. At 60 days post-discharge, 8.4% had new CKD. At discharge, 3% of all patients were dialysis dependent. Baseline CKD (p = 0.030) and CHF (p = 0.037) were associated with non-recovery at 60 days post-discharge. Conclusions: History of CHF, severity of AKI, and ICU admission are predictors of non-recovery of kidney function in patients with COVID-19 and AKI.