Elevated blood urea nitrogen level as a predictor of mortality in patients admitted for decompensated heart failure.
BACKGROUND
Hospitalization for decompensated heart failure is associated with high mortality after discharge. In heart failure, renal function involves both cardiovascular and hemodynamic properties. We studied the relation between renal dysfunction and mortality in patients admitted for decompensated heart failure.


METHODS
The prognostic importance of four measures of renal function-blood urea nitrogen, serum creatinine, blood urea nitrogen/creatinine ratio, and estimated creatinine clearance-was evaluated in 541 patients (mean [+/- SD] age, 63 +/- 14 years; 377 men [70%]) with a previous diagnosis of heart failure (96% with New York Heart Association class III or IV symptoms) who were admitted for clinical decompensation.


RESULTS
During a mean follow-up of 343 +/- 185 days, 177 patients (33%) died. In multivariable Cox regression models, the risk of all-cause mortality increased with each quartile of blood urea nitrogen, with an adjusted relative risk of 2.3 in patients in the upper compared with the lower quartiles (95% confidence interval [CI]: 1.3 to 4.1; P = 0.005). Creatinine and estimated creatinine clearance were not significant predictors of mortality after adjustment for other covariates. Blood urea nitrogen/creatinine ratio yielded similar prognostic information as blood urea nitrogen (adjusted relative risk = 2.3; 95% CI: 1.4 to 3.8; P = 0.0007 for patients in the upper compared with the lower quartiles).


CONCLUSIONS
Blood urea nitrogen is a simple clinical variable that provides useful prognostic information in patients admitted for decompensated heart failure. In this setting, elevated blood urea nitrogen levels probably reflect the cumulative effects of hemodynamic and neurohormonal alterations that result in renal hypoperfusion.
Aronson
Doron
D
Division of Cardiology, Rambam Medical Center, Haifa, Israel.
Mittleman
Murray A
MA
Burger
Andrew J
AJ
D000368:Aged; D015415:Biomarkers / Q000097:blood; D001806:Blood Urea Nitrogen; D002423:Cause of Death; D003404:Creatinine / Q000378:metabolism; D019332:Endothelin-1 / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000378:metabolism* / Q000401:mortality*; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010343:Patient Admission; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012083:Renin / Q000378:metabolism; D013223:Statistics as Topic; D016019:Survival Analysis
D015415:Biomarkers; D019332:Endothelin-1; D003404:Creatinine; D012083:Renin