Natriuretic peptide fragments as possible biochemical markers of hypertension in the elderly

To study the relationship between C-type natriuretic peptide (NT-proCNP) and other natriuretic peptides, such as pro-atrial natriuretic peptide [proANP(1-98)] and N-terminal pro-brain natriuretic peptide (NT-proBNP), in the elderly, investigating also their correlation with other traditional clinical markers of the hypertensive condition.

NT-proCNP, NT-proBNP and proANP(1-98) were measured in 57 elderly patients. They were hypertensive patients (n = 36) and normotensive controls (n = 21). Their anthropometric parameters, including Winsor's index and total and high-density lipoprotein cholesterol, were determined.

A diagnostic role of NT-proBNP in hypertensive patients was detected by a model of logistic regression, which gave a significant result [odds ratio (OR) 1.0115, P = 0.0184]. By this model the area (AUC) under the receiver-operating characteristic (ROC) curve was 0.69 ± 0.071 (P = 0.0075). On the basis of the ROC curve, the calculated serum NT-proBNP cut-off for the prediction of hypertension was greater than 164 pmol/l - the value being provided with a sensitivity of 89% coupled with a specificity of 55%. NT-proCNP and proANP(1-98) did not predict the hypertensive condition, although significant correlations were detected with serum lipid profile and creatinine levels.

By using the logistic regression analysis, NT-proBNP was identified as a significant predictor of hypertension, whereas NT-proCNP and proANP circulating levels were not shown to reliably predict the hypertensive condition. Further validation by means of larger cohort studies is undoubtedly needed to assess the use of all three peptides to increase the performance of a possible test for the prediction of the hypertensive condition in humans.