N-Terminal Pro–B-Type Natriuretic Peptide Variability in Stable Dialysis Patients

Abstract

Background and objectives Monitoring N-terminal pro-B-type natriuretic peptide (NT-proBNP) may be useful for assessing cardiovascular risk in dialysis patients. However, its biologic variation is unknown, hindering the accurate interpretation of serial concentrations. The aims of this prospective cohort study were to estimate the within-and between-person coefficients of variation of NT-proBNP in stable dialysis patients, and derive the critical difference between measurements needed to exclude biologic and analytic variation.Design, setting, participants, & measurements Fifty-five prevalent hemodialysis and peritoneal dialysis patients attending two hospitals were assessed weekly for 5 weeks and then monthly for 4 months between October 2010 and April 2012. Assessments were conducted at the same time in the dialysis cycle and entailed NT-proBNP testing, clinical review, electrocardiography, and bioimpedance spectroscopy. Patients were excluded if they became unstable.Results This study analyzed 136 weekly and 113 monthly NT-proBNP measurements from 40 and 41 stable patients, respectively. Results showed that 22% had ischemic heart disease; 9% and 87% had left ventricular systolic and diastolic dysfunction, respectively. Respective between-and within-person coefficients of variation were 153% and 27% for weekly measurements, and 148% and 35% for monthly measurements. Within-person variation was unaffected by dialysis modality, hydration status, inflammation, or cardiac comorbidity. NT-proBNP concentrations measured at weekly intervals needed to increase by at least 46% or decrease by 84% to exclude change due to biologic and analytic variation alone with 90% certainty, whereas monthly measurements needed to increase by at least 119% or decrease by 54%. ConclusionsThe between-person variation of NT-proBNP was large and markedly greater than within-person variation, indicating that NT-proBNP testing might better be applied in the dialysis population using a relativechange strategy. Serial NT-proBNP concentrations need to double or halve to confidently exclude change due to analytic and biologic variation alone.

Carvedilol and Cardiac Biomarkers in Dialysis Patients: Secondary Analysis of a Randomized Controlled Trial

“…The reference change value (RCV) can be calculated to determine the degree of increase that would be considered a clinically meaningful change (over and above analytic and biological variation) [32]. In dialysis patients undergoing monthly measurements, a clinically meaningful change in NT-proBNP required a decrease of 54% or an increase of 119% [33] and for hs-TnT required a decrease of 25% or increase of 34% [34]. Furthermore, the between person variability for both biomarkers in these studies was very high.…”

N-Terminal Pro-B-Type Natriuretic Peptide as a Biomarker for Loss of Muscle Mass in Prevalent Hemodialysis Patients

“…Additionally, the single-point measurement of NT-proBNP, as well as the other biomarkers of hsCRP, IL-6 and adiponection, did not permit accurate evaluation. Fahim et al reported on the within–person coefficient of variation of NT-proBNP in patients under HD [42]. In the Fahim study, weekly and monthly variations of NT-proBNP were 27% and 35%, respectively; however, the values of NT-proBNP in patients with higher NT-proBNP were maintained at higher levels during the monitoring period [42].…”

“…Fahim et al reported on the within–person coefficient of variation of NT-proBNP in patients under HD [42]. In the Fahim study, weekly and monthly variations of NT-proBNP were 27% and 35%, respectively; however, the values of NT-proBNP in patients with higher NT-proBNP were maintained at higher levels during the monitoring period [42]. Moreover, the variations of NT-proBNP were not associated with hydration status, inflammation, or cardiac comorbidity [42].…”

Cardiovascular Disease in Dialysis Patients

“…B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NT pro-BNP) may also have a role in predicting CVD and all-cause mortality in ESKD [168]. The between-person variability of NT pro-BNP is considerable in stable HD patients, likely accounted for by differences in fluid status, residual kidney function, dialysis prescription and underlying cardiac pathologies [169]. However, the within-person variation is markedly smaller and thus may be of greater prognostic significance [169].…”

“…The between-person variability of NT pro-BNP is considerable in stable HD patients, likely accounted for by differences in fluid status, residual kidney function, dialysis prescription and underlying cardiac pathologies [169]. However, the within-person variation is markedly smaller and thus may be of greater prognostic significance [169]. In a prospective cohort study of baseline serum NT pro-BNP levels in 230 PD patients, the adjusted HR for all-cause mortality and cardiovascular mortality of the fourth quartile were 4.97 (1.35-18.28, p = 0.016) and 7.50 (1.36-41.39, p = 0.021) respectively, compared with the first quartile [170].…”