Race and mortality after acute renal failure

Abstract

Black patients receiving dialysis for end-stage renal disease in the United States have lower mortality rates than white patients. Whether racial differences exist in mortality after acute renal failure is not known. We studied acute renal failure in patients hospitalized between 2000 and 2003 using the Nationwide Inpatient Sample and found that black patients had an 18% (95% confidence interval [CI] 16 to 21%) lower odds of death than white patients after adjusting for age, sex, comorbidity, and the need for mechanical ventilation. Similarly, among those with acute renal failure requiring dialysis, black patients had a 16% (95% CI 10 to 22%) lower odds of death than white patients. In stratified analyses of patients with acute renal failure, black patients had significantly lower adjusted odds of death than white patients in settings of coronary artery bypass grafting, cardiac catheterization, acute myocardial infarction, congestive heart failure, pneumonia, sepsis, and gastrointestinal hemorrhage. Black patients were more likely than white patients to be treated in hospitals that care for a larger number of patients with acute renal failure, and black patients had lower in-hospital mortality than white patients in all four quartiles of hospital volume. In conclusion, in-hospital mortality is lower for black patients with acute renal failure than white patients. Future studies should assess the reasons for this difference.

Figure 1

Multivariable-adjusted odds ratio for death among black patients with ARF (A) and without ARF (B), stratified by selected concomitant procedures and diagnoses. Multivariable models adjusted for age, gender, need for mechanical ventilation, and D-CI. The reference group is white patients with the corresponding diagnoses and/or procedure. Point estimates are represented by the symbol and 95% confidence intervals by horizontal lines. Values <1 denote lower in-hospital mortality for black patients. Results are stratum specific (i.e., represent differences in odds for death for black versus white patients for a given procedure or diagnosis) and are not comparable across strata. P values for the interaction term (ARF * race) were as follows: CABG <0.001, catheter/PCI <0.001, AMI <0.001, CHF 0.72, CKD 0.31, pneumonia <0.001, acute pancreatitis 0.09, sepsis <0.001, gastrointestinal (GI) hemorrhage 0.25, and acute hepatic failure 0.86.

Figure 2

Multivariable-adjusted odds ratio for death among black patients with ARF-D and selected concomitant procedures and diagnoses. Multivariable models adjusted for age, gender, need for mechanical ventilation, and D-CI. The reference group is white patients with the corresponding diagnoses and/or procedure. Point estimates are represented by the symbol and 95% confidence intervals by horizontal lines. Values <1 denote lower in-hospital mortality for black patients. Results are stratum specific (i.e., represent differences in odds for death for black versus white patients with ARF-D for a given procedure or diagnosis) and are not comparable across strata.