Anaemia and renal dysfunction are independently associated with BNP and NT-proBNP levels in patients with heart failure

BACKGROUND: Anaemia may affect B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) levels, but this has not been well described in heart failure (HF) patients without the exclusion of patients with renal dysfunction. AIMS: To study the influence of both anaemia and renal function on BNP and NT-proBNP levels in a large group of hospitalised HF patients. METHODS AND RESULTS: We studied 541 patients hospitalised for HF (mean age 71+/-11 years, 62% male, and left ventricular ejection fraction 0.33+/-0.14). Of these patients, 30% (n=159) were anaemic (women: Hb<7.5 mmol/l, men: Hb<8.1 mmol/l). Of the 159 anaemic patients, 73% had renal dysfunction (eGFR<60 ml/min/1.73 m2) and of the non-anaemic patients, 57% had renal dysfunction. BNP and NT-proBNP levels were measured in all patients before discharge. In multivariable analyses both plasma haemoglobin and eGFR were independently related to the levels of BNP and NT-proBNP (standardised beta's of -0.16, -0.14 [BNP] and -0.19, -0.26 [NT-proBNP] respectively, P-values<0.01). CONCLUSION: Anaemia and renal dysfunction are related to increased BNP and NT-proBNP levels, independent of the severity of HF. These results indicate that both anaemia and renal dysfunction should be taken into consideration during the interpretation of BNP and NT-proBNP levels in HF patients.