The value of B-type natriuretic peptide plasma concentrations in very old people with chronic peripheral oedema

Chronic peripheral oedema is frequent in old patients, and very often results from multiple causes.

To investigate whether determination of B-type natriuretic peptide plasma concentration helps with the diagnosis of chronic peripheral oedema aetiologies.

This was a cross-sectional observational study conducted in geriatric hospital wards (intermediate and long-term care) on consecutive in-hospital patients aged>75 years with chronic peripheral oedema and no dyspnoea. From medical history, physical examination, routine biological tests and chest radiography, two investigators determined the aetiologies of oedema, with special attention paid to recognizing chronic heart failure. This reference diagnosis was compared with the clinical diagnosis mentioned in the medical chart. Brain natriuretic peptide plasma concentrations were measured soon after the investigators' visit.

Among the 141 patients (113 women and 28 men) aged 86±6 years, a single aetiology was identified in 53 (38%), and multiple aetiologies in 84 (60%). The main aetiologies were venous insufficiency (69%), chronic heart failure (43%), hypoproteinaemia (38%) and drug-induced oedema (26%). Chronic heart failure was frequently misdiagnosed by attending clinicians (missed in 18 cases and wrongly diagnosed in 14 cases). Brain natriuretic peptide concentration was significantly higher in patients with chronic heart failure than in those without: median (interquartile range) 490 (324-954) versus 137 (79-203) pg/mL, respectively (P<0.0001). The receiver operating characteristic curve showed that a concentration of 274pg/mL was appropriate for diagnosing chronic heart failure, with a specificity of 0.89 and a sensitivity of 0.82. Brain natriuretic peptide concentrations above this cut-off were significantly and independently associated with the diagnosis of chronic heart failure.

Chronic heart failure is frequently misdiagnosed in old patients with chronic peripheral oedema, and B-type natriuretic peptide plasma concentration helped to improve the diagnosis of this condition and identify chronic heart failure.