BACKGROUND

Multiple studies have identified risk factors for acute kidney injury (AKI) in hospitalized patients, but less is known about factors associated with AKI severity, including non-recovery of AKI.

METHODS

Retrospective cohort study of adults (≥18 years) hospitalized between 2014 and 2017 at three US academic medical centers. Study outcomes included incidence of AKI and non-recovery from AKI at hospital discharge in those who survived hospitalization. AKI was defined by KDIGO serum creatinine criteria. Non-AKI recovery was defined as persistent AKI stage ≥1 at time of discharge. Multivariable models assessed the association of risk factors for each outcome, focusing on race, diabetes, and obesity (BMI ≥ 30 versus <30 kg/m), and adjusting for potential confounders.

RESULTS

Among 56 056 patients included in the study (mean age 57, 25% Black, 48% women), 12 954 (23%) developed AKI. In adjusted models, Black race [odds ratio (OR) 1.26, 95% confidence interval (CI): 1.20, 1.32], diabetes (OR 1.14, 95% CI: 1.08, 1.19) and obesity (OR 1.14, 95% CI: 1.10, 1.20) were all associated with incident AKI. A total of 3591 of the 11 672 (30.8%) patients with AKI who survived until discharge had AKI non-recovery. In adjusted models, obesity (OR 1.27, 95% CI: 1.17, 1.39) was independently associated with higher risk of AKI non-recovery at hospital discharge.

CONCLUSIONS

Black race, diabetes, and obesity were associated with the development of AKI in hospitalized patients, but only obesity was associated with non-recovery from AKI at hospital discharge. These findings emphasize the growing relevance of obesity as an epidemiological risk factor of AKI.