Association of Race with In-Hospital and Post-Hospitalization Mortality in Patients with Acute Kidney Injury

Introduction: Acute kidney injury (AKI) is known to be associated with increased mortality, and racial differences in hospital mortality exist in patients with AKI. However, it remains to be seen whether racial differences exist in post-hospitalization mortality among AKI patients.

Methods: We analyzed data of adult AKI patients admitted to the University of Virginia Medical Center between January 1, 2001, and December 31, 2015, to compare in-hospital and post-hospitalization mortality among hospitalized black and white patients with AKI. Multivariable logistic regression analysis was used to analyze the association between race and in-hospital mortality, and 90-day post-hospitalization mortality among AKI patients that were discharged. Kaplan-Meier survival curve was used to evaluate long-term survival between black and white patients.

Results: Black patients had lower in-hospital mortality than white patients after adjusting for age, sex, estimated glomerular filtration rate, hospital length of stay, severity of AKI, comorbidities, and the need for dialysis and mechanical ventilation (odds ratio: 0.82; 95% confidence interval, 0.70-0.96, p = 0.0015). Similarly, at 90-day post-hospitalization, black patients had significantly lower adjusted odds of death than white patients (odds ratio: 0.64; 95% confidence interval, 0.46-0.93; p = 0.008). The median length of follow-up was 11.9 months (0.6-46.7 months). Kaplan-Meier survival curve showed that long-term survival was significantly better in black patients compared to white patients (median duration of survival; 39.7 vs. 24.8 months; p ≤ 0.001).

Conclusions: Black patients with AKI had lower in-hospital mortality, 90-day post-hospitalization mortality, and better long-term survival rates compared to white patients with AKI.