The Association Between Depressive Symptoms and N-Terminal Pro–B-Type Natriuretic Peptide With Functional Status in Patients With Heart Failure

Background N-terminal pro-B-type natriuretic peptide (NT-proBNP) and depressive symptoms are each associated with functional status in patients with heart failure (HF), but their association together with functional status has not been examined. Objective The aim of this study was to determine whether functional status scores differ as a function of depressive symptoms and NT-proBNP levels considered together. Methods We studied 284 patients with HF who were divided into 4 groups based on the median split of NT-proBNP levels and cut point for depressive symptoms (Beck Depression Inventory ≥ 14): (1) low NT-proBNP of 562.5 pg/mL or less without depressive symptoms, (2) low NT-proBNP of 562.5 pg/mL or less with depressive symptoms, (3) high NT-proBNP of greater than 562.5 pg/mL without depressive symptoms, and (4) high NT-proBNP of greater than 562.5 pg/mL with depressive symptoms. The Duke Activity Status Index was used to assess functional status. Results Nonlinear regression demonstrated that patients without depressive symptoms were more than twice as likely to have higher (better) functional status scores than patients with depressive symptoms regardless of NT-proBNP levels after controlling for age, gender, prescribed antidepressants, and body mass index. Functional status levels of patients with low NT-proBNP did not differ from those with high NT-proBNP in the presence of depressive symptoms. Conclusion When examined together, depressive symptoms rather than NT-proBNP levels predicted functional status. Clinical implications Adequate treatment of depressive symptoms may lead to better functional status regardless of HF severity.