Correlates of N-terminal prohormone brain natriuretic peptides in African Americans with hypertensive chronic kidney disease: the African American Study of Kidney Disease and Hypertension.

BACKGROUND/AIMS: The N-amino-terminal fragment of the prohormone B-type natriuretic peptide (NT-proBNP) is a marker of cardiac stress and elevated levels are indicative of heart failure. Few correlates of NT-proBNP levels have been identified in persons with moderate chronic kidney disease (CKD), and data from those without heart failure and from African Americans are especially limited. METHODS: The African American Study of Kidney Disease and Hypertension (AASK) enrolled nondiabetic African Americans with hypertensive kidney disease (glomerular filtration rate [GFR] = 20-65 ml/min/1.73 m(2)) and no evidence of clinical heart failure. NT-proBNP was measured in 982 AASK participants. RESULTS: In unadjusted analyses, GFR (r = -0.39; p < 0.001), hematocrit (r = -0.21; p < 0.001) and body mass index (BMI; r = -0.07; p = 0.04) were inversely correlated, and systolic blood pressure (r = 0.30; p < 0.001) and log UPCR (r = 0.32; p < 0.001) were positively correlated with log NT-proBNP levels. After adjustment for potential confounders, lower GFR and hematocrit and higher systolic blood pressure and protein:creatinine ratio remained significantly associated with higher NT-proBNP. CONCLUSION: Lower GFR and hematocrit, and higher urinary protein excretion may be associated with volume expansion in CKD. These results suggest that these processes are associated with increased NT-proBNP in CKD and may play a role in the development of heart failure.