Background: Both acute renal failure (ARF) and female sex are strongly associated with mortality after open-heart surgery. This study analyzes the effect of sex and race on the incidence of ARF after open-heart surgery and its influence on mortality.
Methods: A total of 24,660 patients underwent open-heart surgery at the Cleveland Clinic Foundation (Cleveland, OH) from 1993 to 2000. The primary outcome was ARF defined as ARF requiring dialysis, 50% or greater decline in glomerular filtration rate (GFR) not requiring dialysis, or 50% or greater decline in GFR relative to baseline or requirement of dialysis. The secondary outcome was all-cause hospital mortality.
Results: The overall frequency of ARF requiring dialysis after open-heart surgery was 1.82%. The frequency was greater in women (2.36%) than men (1.60%; P < 0.0001) and blacks (2.94%) than nonblacks (1.70%; P < 0.0001) by univariate analysis. By multivariate analysis, risk for ARF requiring dialysis in women was 1.61 (confidence interval [CI], 1.27 to 2.05; P < 0.0001), but race was not a risk factor. The overall postoperative mortality rate was 2.2%, and for patients with ARF requiring dialysis, it was 61.2% (women, 68.6% versus men, 56.5%; P = 0.01) with an odds ratio of 49.29, whereas in patients with ARF not requiring dialysis, it was 14.1% (women, 13.3% versus men 14.6%; P = 0.63) with an odds ratio of 7.18.
Conclusion: Female sex is an independent risk factor for developing ARF after open-heart surgery. The influence of race on risk for ARF is less clear. Regardless of its definition, ARF is strikingly associated with a high risk for mortality.