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.