title: eGFR and Outcomes in Patients with Acute Decompensated Heart Failure with or without Elevated BUN.
abstract: OBJECTIVE
  In patients with heart failure, the association of renal dysfunction and BUN levels with outcomes is unclear. The aim of our study was to investigate the association between the eGFR at discharge and outcomes in patients with heart failure with or without an elevated BUN level at discharge.
  
  
  METHODS
  Of 4842 patients enrolled in the Acute Decompensated Heart Failure Syndromes Registry, 4449 patients discharged alive after hospitalization for acute decompensated heart failure were investigated to assess the association of eGFR in the context of serum BUN level at discharge with all-cause mortality. The enrolled patients were divided into four groups on the basis of the discharge levels of eGFR (<45 or ≥45 ml/min per 1.73 m(2)) and BUN (≥25 or <25 mg/dl). The median follow-up period after discharge was 517 (381-776) days.
  
  
  RESULTS
  The all-cause mortality rate after discharge was 19.1%. After adjustment for multiple comorbidities, an eGFR<45 ml/min per 1.73 m(2) was associated with a significantly higher risk of all-cause mortality in patients with a BUN≥25 mg/dl (hazard ratio, 1.58; 95% confidence interval, 1.33 to 1.88; P<0.001) but not in patients with a BUN<25 mg/dl (hazard ratio, 0.97; 95% confidence interval, 0.76 to 1.26; P=0.84) relative to those with an eGFR≥45 ml/min per 1.73 m(2) and a BUN<25 mg/dl. Among patients with an eGFR≥45 ml/min per 1.73 m(2), a BUN≥25 mg/dl was associated with a significantly higher risk of all-cause mortality than a BUN<25 mg/dl (hazard ratio, 1.34; 95% confidence interval, 1.04 to 1.73; P=0.02).
  
  
  CONCLUSIONS
  We showed that elevation of BUN at discharge significantly modified the relation between eGFR at discharge and the risk of all-cause mortality after discharge, suggesting that the association between eGFR and outcomes may be largely dependent on concomitant elevation of BUN.
authors.affiliation: Division of Cardiology, Sekikawa Hospital, Tokyo, Japan; kkajimoto@gmail.com.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Kajimoto
authors.affiliation: Department of Internal Medicine, Cardiology, and Intensive Care Unit, Nippon Medical School Musashi-Kosugi Hospital, Kanagawa, Japan; and.
authors.forename: Naoki
authors.initials: N
authors.lastname: Sato
authors.affiliation: Department of Internal Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Teruo
authors.initials: T
authors.lastname: Takano
mesh_terms: D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D001806:Blood Urea Nitrogen; D005260:Female; D005919:Glomerular Filtration Rate; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality*; D006801:Humans; D007564:Japan; D007668:Kidney / Q000503:physiopathology*; D007674:Kidney Diseases / Q000097:blood / Q000175:diagnosis / Q000401:mortality* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010351:Patient Discharge; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D015854:Up-Regulation
keywords: Comorbidity; Follow-Up Studies; Humans; Patient Discharge; Registries; blood urea nitrogen; glomerular filtration rate; heart failure; hospitalization; outcomes assessment