EGFR and outcomes in patients with acute decompensated heart failure with or without elevated BUN

Abstract

Background and objectives In patients with heart failure, the association of renal dysfunction and BUN levels with outcomes is unclear. The aimof our studywas 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. Design, setting, participants, & measurements Of 4842 patients enrolled in the Acute Decompensated Heart Failure Syndromes Registry, 4449 patients discharged alive after hospitalization for acute decompensated heart failurewere investigated to assess the association of eGFR in the context of serumBUNlevel at discharge with allcause mortality. The enrolled patients were divided into four groups on the basis of the discharge levels of eGFR (<45 or ³45 ml/min per 1.73 m2) and BUN(³25 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 m2 was associated with a significantly higher risk of all-cause mortality in patients with a BUN³25 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 eGFR³45 ml/min per 1.73 m2 and a BUN,25 mg/dl. Among patients with an eGFR$45 ml/min per 1.73 m2, 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.