Abstract 80: Amino-terminal Pro-B-type Natriuretic Peptide (NT-Pro-BNP) And Risk Of Stroke: The Reasons For Geographic And Racial Differences In Stroke (REGARDS) Cohort

Abstract

Background: Higher NT-Pro-BNP is a biomarker of cardiac dysfunction associated with risk of future heart failure and atrial fibrillation, and as such may be a marker of stroke risk. Methods: REGARDS enrolled 30,239 US participants in 2003-07 (41% black, 59% white, 55% living in the southeastern stroke belt). With 5.4 years follow-up, baseline NT-Pro-BNP was measured in 610 subjects with first-time stroke and a 1017 person cohort random sample free from prebaseline stroke. Cox proportional hazards models were used to calculate hazard ratios (HR) of stroke by quartiles of NT-Pro-BNP. Net reclassification improvement (NRI) was calculated using the category free NRI statistic. Results: Baseline NT-Pro-BNP was higher with older age, in whites, women, and with diabetes, impaired kidney function, atrial fibrillation, prebaseline heart disease, lower body-mass index and left ventricular hypertrophy by ECG. Levels were higher in those who developed incident stroke. Adjusting for age, race and sex there was an increased HR of stroke with increasing quartiles of NT-Pro-BNP (Model 1 in table); subjects in the 4 th versus 1 st quartile had a 3.7-fold increased stroke risk. Adjustment for income, education and traditional stroke risk factors attenuated this HR to 3.0. There was minimal impact of added adjustment for kidney function, BMI and heart failure. Associations did not differ by age, sex, race or kidney disease status. Based on NRI, predicted stroke risk was more accurate in 27% of participants if NT-Pro-BNP was measured with traditional stroke risk factors (p<0.001). Discussion: NT-Pro-BNP was a major risk marker for stroke and improved risk classification. By comparison, in this cohort the HRs of stroke were 1.5 for atrial fibrillation and 1.8 for hypertension. More work is needed to confirm that measuring NT-Pro-BNP improves clinical prediction scores for stroke.