title: Blood urea nitrogen/creatinine ratio identifies a high-risk but potentially reversible form of renal dysfunction in patients with decompensated heart failure.
abstract: BACKGROUND
  Identifying reversible renal dysfunction (RD) in the setting of heart failure is challenging. The goal of this study was to evaluate whether elevated admission blood urea nitrogen/creatinine ratio (BUN/Cr) could identify decompensated heart failure patients likely to experience improvement in renal function (IRF) with treatment.
  
  
  RESULTS
  Consecutive hospitalizations with a discharge diagnosis of heart failure were reviewed. IRF was defined as ≥20% increase and worsening renal function as ≥20% decrease in estimated glomerular filtration rate. IRF occurred in 31% of the 896 patients meeting eligibility criteria. Higher admission BUN/Cr was associated with in-hospital IRF (odds ratio, 1.5 per 10 increase; 95% confidence interval [CI], 1.3-1.8; P<0.001), an association persisting after adjustment for baseline characteristics (odds ratio, 1.4; 95% CI, 1.1-1.8; P=0.004). However, higher admission BUN/Cr was also associated with post-discharge worsening renal function (odds ratio, 1.4; 95% CI, 1.1-1.8; P=0.011). Notably, in patients with an elevated admission BUN/Cr, the risk of death associated with RD (estimated glomerular filtration rate <45) was substantial (hazard ratio, 2.2; 95% CI, 1.6-3.1; P<0.001). However, in patients with a normal admission BUN/Cr, RD was not associated with increased mortality (hazard ratio, 1.2; 95% CI, 0.67-2.0; P=0.59; p interaction=0.03).
  
  
  CONCLUSIONS
  An elevated admission BUN/Cr identifies decompensated patients with heart failure likely to experience IRF with treatment, providing proof of concept that reversible RD may be a discernible entity. However, this improvement seems to be largely transient, and RD, in the setting of an elevated BUN/Cr, remains strongly associated with death. Further research is warranted to develop strategies for the optimal detection and treatment of these high-risk patients.
authors: Department of Medicine, Cardiovascular Division, University of Pennsylvania, Philadelphia, PA, USA.
authors: Meredith A
authors: MA
authors: Brisco
authors: Steven G
authors: SG
authors: Coca
authors: Jennifer
authors: J
authors: Chen
authors: Anjali Tiku
authors: AT
authors: Owens
authors: Brian D
authors: BD
authors: McCauley
authors: Stephen E
authors: SE
authors: Kimmel
authors: Jeffrey M
authors: JM
authors: Testani
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D001806:Blood Urea Nitrogen; D059347:Cardio-Renal Syndrome / Q000097:blood / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology; D016009:Chi-Square Distribution; D003404:Creatinine / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006333:Heart Failure / Q000097:blood / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D007668:Kidney / Q000378:metabolism / Q000503:physiopathology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D010343:Patient Admission; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; D003404:Creatinine