NPPB and heart failure: In longitudinal studies of the oldest old, elevated NT-proBNP predicted worsening performance on activities of daily living and cognitive decline (Leiden 85+ study),37 and left ventricular mass predicted functional decline in terms of activities of daily living (Jerusalem longitudinal study).38 Additionally, higher NT-proBNP was associated with incident disability.39 NT-proBNP is an important biomarker in the diagnosis of heart failure,40 and the upper limit of normal for NT-proBNP is 125 pg/mL.