N-terminal pro B-type natriuretic peptide levels in a paediatric haemodialysis cohort

Accurate volume assessment is essential in the management of children on dialysis as excess volume is a key cause of arterial hypertension and is associated with the development of hypertension-mediated organ injury. Our objective was to describe NT-proBNP concentrations in a cohort of children receiving in-centre chronic intermittent haemodialysis with preserved systolic cardiac function and to evaluate relevant associations.

This was a retrospective study including prevalent children aged < 18 years who were established on IHD and had preserved systolic cardiac function.

There were 24 children, mean age 10.3 ± 5.8 years, of whom 8 had urine output < 150 mL/day, median dialysis vintage 130.3 ± 364.8 days. There were 161 post-IHD NT-proBNP measurements performed, of which 130 measurements (80.7%) were abnormal when defined as a concentration above 598 ng/L; median (IQR) 2046 (794, 5275) ng/L [Log 3.34 ± 0.58 ng/L]. Children with urine output > 150 mL/day had a mean ± SD, log NT-proBNP of 3.25 ± 0.51 ng/L and those with < 150 mL/day 3.43 ± 0.65 ng/L (P = 0.047). Following multivariable regression analysis, log NT-proBNP positively associated with systolic blood pressure z-score (SBP_z-POST) (β = 0.15, P < 0.01) and non-White ethnicity (β = 0.10, P = 0.02) and negatively with UO > 150 mL/day (β = -0.28, P < 0.01) and haemoglobin concentrations (β = -0.01, P = 0.01). There was no significant association between log NT-proBNP with primary kidney disease, sex or interdialytic weight gain.

We observed most post-haemodialysis NT-proBNP measurements to be abnormal despite preserved systolic cardiac function in children established on IHD. The utility of a single measurement remains limited and serial measurements and improved understanding of reasons for variation in intra-patient measurements may be more useful when used alongside standard clinical parameters in this population.