Relationship of N-Terminal fragment of Pro-B-Type Natriuretic Peptide and copeptin with erythrocytes-related parameters: A population-based study.

Background: Plasma levels of natriuretic peptides (NP) have been inversely related to hemoglobin (Hb) concentration in prior studies. However, the mechanism underlying this association remains unclear. We aimed to obtain further insights into potential mechanisms for this correlation in a cohort of healthy adults.
Methods: A population-based study was performed among 2113 healthy adults aged 25-41years. Relationships of N-Terminal fragment of Pro-B-Type Natriuretic Peptide (NT-proBNP) or copeptin with volume-dependent (Hb, hematocrit (Hct), erythrocyte count (EC), mean corpuscular Hb concentration (MCHC)) and volume-independent (mean corpuscular volume (MCV), mean corpuscular Hb (MCH)) erythrocyte-related parameters were assessed using sex-specific multivariable linear regression analyses.
Results: The median age was 36.7years. Median NT-proBNP (ng/L) levels were 49.5 and 20 among women and men, respectively (p<0.0001). Mean (standard deviation) Hb (g/L) levels were 130.1(9.1) and 149.7(8.6) among women and men, respectively (p<0.0001). Among men, multivariable adjusted β-coefficients (95% confidence interval) for NT-proBNP were -1.68 (-2.36; -1.01), p<0.0001 for Hb; -0.38 (-0.57; -0.20), p<0.0001 for Hct; -0.06 (-0.09; -0.04), p<0.0001 for EC; -0.78 (-1.50; -0.07), p=0.03 for MCHC; 0.26 (-0.04; 0.56), p=0.09 for MCV; and 0.03 (-0.08; 0.14), p=0.61 for MCH. For copeptin, these relationships were 1.36 (0.39; 2.32), p=0.006; 0.41 (0.15; 0.68), p=0.002; 0.06 (0.02; 0.09), p=0.002; -0.17 (-1.19; 0.86), p=0.75; -0.12 (-0.55; 0.31), p=0.58 and -0.05 (-0.21; 0.10), p=0.52. Similar results were observed among women.
Conclusions: We found significant relationships of NT-proBNP and copeptin with volume-dependent but not volume-independent erythrocyte-related parameters, suggesting that hemodilution may at least in part explain these associations.
(Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)