[NT-proBNP in elderly inpatients: an useful marker for detecting heart failure?].

In this study we try to determine a cut off for detecting heart failure (HF) with the highest sensitivity and specificity in a population of hospitalized people aged > or = 65 years and to identify potential confounding variables for the interpretation of plasma concentration of the marker. We evaluated 212 consecutive patients admitted to our Department of Medicine, the only inclusion criterion being an age > or = 65 years. We identified a group with clinical and/or instrumental HF, and among remaining patients we selected a normal group without obvious cardiac disease. The strongest predictors of higher levels of NT-proBNP resulted age and free-triiodothyronine as in all models they were strongly associated with Log NT-proBNP. Using receiver-operating characteristics (ROC) curves, we found an optimal discriminatory value for detecting HF in 879 pg/ml for subjects aged between 65 and 74 years and 1658 pg/ml for subjects aged > or = 75 years. In elderly hospitalized patients the discriminatory cut offs of NT-proBNP for the diagnosis of HF are significantly higher than community derived reference values. Adjustments for the independent effects of age and other confounding variables appear necessary.