NT-proBNP and Echocardiographic Parameters for Prediction of Cardiovascular Outcomes in Patients with CKD Stages G2-G4.

BACKGROUND AND OBJECTIVES: Natriuretic peptides and echocardiographic parameters both predict cardiovascular events in patients with CKD. However, it is unknown whether simultaneous assessment of amino-terminal probrain natriuretic peptide (NT-proBNP) and echocardiographic parameters provides complementary or redundant predictive information; in the latter case, one of these two might be dispensable. We aimed to analyze the implications of using NT-proBNP alone, echocardiographic parameters alone, or a combination of both for prediction of adverse cardiovascular outcome.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Within the longitudinal Cardiovascular and Renal Outcome in CKD 2-4 Patients-The Fourth Homburg Evaluation Study, we prospectively studied 496 patients with CKD stages G2-G4, in whom we measured NT-proBNP. Left ventricular mass index, left atrial volume index, diastolic left ventricular function, and systolic left ventricular function were assessed echocardiographically. During 4.5±2.0 years of follow-up, the occurrence of (1) decompensated heart failure or all-cause mortality and (2) atherosclerotic events or all-cause mortality was recorded. We assessed the association of NT-proBNP and echocardiographic parameters with outcome (using Cox models) and evaluated the increased discriminative value associated with the addition of echocardiographic parameters and NT-proBNP (using integrated discrimination improvement and net reclassification improvement).

RESULTS: During follow-up, 104 patients suffered decompensated heart failure or all-cause mortality, and 127 patents had atherosclerotic events or all-cause mortality. In univariable analyses, NT-proBNP and echocardiographic parameters predicted cardiovascular events. NT-proBNP remained an independent predictor for both end points in multivariate analysis, whereas left ventricular mass index, left atrial volume index, and diastolic left ventricular function did not. The addition of NT-proBNP on top of clinical and various echocardiographic variables was associated with improvements in reclassification for decompensated heart failure or all-cause mortality (integrated discrimination improvement =6.5%-8.3%; net reclassification improvement =23.1%-27.0%; all P≤0.03). Adding echocardiographic variables on top of clinical variables and NT-proBNP was not associated with significant net reclassification improvement (all P>0.05).

CONCLUSIONS: Our data confirm NT-proBNP is an independent predictor of adverse outcomes in patients with CKD. The additional use of echocardiography for improvement of risk stratification is not supported by our results.