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

Abstract

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.

The Effects of Race on Acute Kidney Injury

“…In our study that included data of 11,567 AKI patients managed at the University of Virginia Health System, we demonstrated that Black patients had lower in-hospital mortality than Whites, with adjusted odds ratio 0.82, 95% confidence interval 0.70–0.96, p = 0.0015. Following further analysis, we also extended the findings of the previous workers by demonstrating Black patients had lower 90-day post-hospitalization mortality and better long-term survival advantage when compared to their White counterparts [ 15 ]. Similarly, data from the United States Renal Data System (2021 USRDS Annual Data Report) also showed a survival advantage for Black populations compared to White populations after 24 months’ follow-up; Black patients had 38,6% death rates compared to 41.7% death rates in White patients.…”

“…Even though African Americans (Blacks) in the general population are at a higher risk of cardiovascular and non-cardiovascular mortality when compared to Whites [ 67 , 68 ], several reports have suggested that a paradox exists for individuals with AKI, with Black patients having better survival rates than their White counterparts [ 15 , 26 , 69 ]. Waikar et al [ 26 ], in their study of hospitalized acute renal failure patients between 2000 and 2003 using the Nationwide Inpatient Sample, showed a survival advantage among Black patients with AKI compared to their White counterparts, with Black patients having 16% (95% confidence interval, 10–20%) lower odds for death than White patients with AKI.…”

“…Similarly, data from the United States Renal Data System (2021 USRDS Annual Data Report) also showed a survival advantage for Black populations compared to White populations after 24 months’ follow-up; Black patients had 38,6% death rates compared to 41.7% death rates in White patients. Previously postulated explanations for this paradoxical finding such as increased access to health care due to medical insurance, “reverse epidemiology” of cardiovascular risk factors, differences in susceptibility to kidney injury, severity of illness, or the response to uremia, warrant additional well-designed investigation [ 15 , 26 ].…”

“…Acute kidney injury describes the sudden loss of kidney function, characterized by ≥0.3 mg/dL (≥26.5 μmol/L) rise in serum creatinine within 48 h or an increase in serum creatinine ≥1.5 times over baseline, which is known or presumed within the prior 7 days, or reduced urinary output of < 0.5 mL/kg/h within 6 h [ 11 ]. Given that AKI has significant clinical consequences, including higher hospitalization rates, increased hospital length of stay, increased in-hospital and post-hospitalization mortality, and higher risk of progression to chronic kidney disease [ 12 , 13 , 14 , 15 ], understanding and addressing how race directly affects patients with AKI is crucial to improving the diagnosis, treatment, and outcomes of AKI in minority racial groups.…”

Incidence, associated factors, and outcomes of acute kidney injury following placement of antibiotic bone cement spacers in two-stage exchange for periprosthetic joint infection: a comprehensive study

“…Reports from other areas have shown that black patients tend to have a higher risk of AKI than white patients, and Asians also have a relatively low incidence of AKI ( Hassan and Balogun, 2022 ). However, black patients with AKI would have a lower in-hospital mortality rate ( Hassan et al., 2021 ). The association between race and AKI in PJI remains unknown, but warrants further investigation to improve prognosis.…”