Clinical deterioration in established heart failure: what is the value of BNP and weight gain in aiding diagnosis?

BACKGROUND: Weight gain and increase in B-Type Natriuretic Peptide have been advocated as means of aiding diagnosis of heart failure. However, there are few data to support the use of these criteria in diagnosing clinical deterioration in patients with established disease. AIMS: This prospective study examines the sensitivity and specificity of absolute and relative changes in BNP and weight in determining the early onset of clinical deterioration in patients with established heart failure.
METHODS: All patients who presented to the outpatient clinic with completed self-reported daily weight books, baseline BNP measurement, outpatient BNP measurement and assessment by a cardiologist blinded to BNP and weight were included. Each patient was determined as clinically stable (CS) or in clinical deterioration (CD). Receiver operating characteristic (ROC) curves and sensitivity and specificity calculations for various absolute and relative BNP and weight changes were carried out.
RESULTS: Weight and BNP changes were examined in 34 CS presentations (mean age 69.5+/-16.1 years) and 43 CD presentations (mean age 70.0+/-10.6 years). ROC analysis demonstrated that neither weight nor BNP changes in absolute or relative values predicted clinical deterioration in this study population adequately (AUC values ranging from 0.64 to 0.66).
CONCLUSIONS: These data demonstrate that increase in body weight and BNP in isolation are not sensitive in assessing clinical deterioration in established heart failure. These observations may need to be emphasized in patient education and to physicians involved in assessment of heart failure patients.