TY - JOUR
T1 - Variability in measures of mineral metabolism in children on hemodialysis
T2 - impact on clinical decision-making
AU - Kakajiwala, Aadil
AU - Jemielita, Thomas O.
AU - Copelovitch, Lawrence
AU - Leonard, Mary B.
AU - Furth, Susan L.
AU - York, Amy
AU - Benton, Maryjane
AU - Hoofnagle, Andrew N.
AU - Windt, Kimberly
AU - Merrigan, Karen
AU - Lederman, April
AU - Denburg, Michelle R.
N1 - Publisher Copyright:
© 2017, IPNA.
PY - 2017/12/1
Y1 - 2017/12/1
N2 - Background: Variability in measures of mineral metabolism has not been studied in pediatric end stage kidney disease. We sought to determine the intra-individual variability in measures of mineral metabolism in children on hemodialysis (HD) and its impact on clinical decision-making. Methods: We conducted a prospective single-center study of children (3.6–17.3 years old) on chronic HD. Serial twice weekly measures of serum calcium, phosphate and intact parathyroid hormone (PTH), as well as weekly measures of fibroblast growth factor 23 (FGF23) and vitamin D metabolites, were obtained over a 12-week period in 10 children. Samples (n = 226) were assayed in a single batch at the end of the study. Results: The median intra-individual coefficient of variation (CV) calculated by 4-week blocks was 5.1–6.5% for calcium, 9.5–14.9% for phosphate and 32.7–33.4% for PTH. The median overall CV for FGF23 was 44.4%. Using the first value of each block as a reference, subsequent values would dictate a discrepant management decision 33–56%, 19–28%, and 30–33% of the time for calcium, phosphate, and PTH, respectively. Adjusting for sex and age, most of the variability in phosphate and PTH was attributable to within-participant variability. For calcium, 49% of the variability was attributable to day of blood collection (Monday vs. Friday). The median (range) of an individual participant’s values within clinical target ranges was 55% (26–86%) for calcium, 58% (0–96%) for phosphate, and 21% (0–64%) for PTH. Conclusions: There is considerable intra-individual variability in measures of mineral metabolism that serve as surrogate markers for bone health in children on HD. Within a 4-week period, at least 20–30% of measures would dictate a discrepant decision from the referent measure of that month. These findings have important implications for clinical decision-making and underscore the need to base therapeutic decisions on trends rather than single measurements.
AB - Background: Variability in measures of mineral metabolism has not been studied in pediatric end stage kidney disease. We sought to determine the intra-individual variability in measures of mineral metabolism in children on hemodialysis (HD) and its impact on clinical decision-making. Methods: We conducted a prospective single-center study of children (3.6–17.3 years old) on chronic HD. Serial twice weekly measures of serum calcium, phosphate and intact parathyroid hormone (PTH), as well as weekly measures of fibroblast growth factor 23 (FGF23) and vitamin D metabolites, were obtained over a 12-week period in 10 children. Samples (n = 226) were assayed in a single batch at the end of the study. Results: The median intra-individual coefficient of variation (CV) calculated by 4-week blocks was 5.1–6.5% for calcium, 9.5–14.9% for phosphate and 32.7–33.4% for PTH. The median overall CV for FGF23 was 44.4%. Using the first value of each block as a reference, subsequent values would dictate a discrepant management decision 33–56%, 19–28%, and 30–33% of the time for calcium, phosphate, and PTH, respectively. Adjusting for sex and age, most of the variability in phosphate and PTH was attributable to within-participant variability. For calcium, 49% of the variability was attributable to day of blood collection (Monday vs. Friday). The median (range) of an individual participant’s values within clinical target ranges was 55% (26–86%) for calcium, 58% (0–96%) for phosphate, and 21% (0–64%) for PTH. Conclusions: There is considerable intra-individual variability in measures of mineral metabolism that serve as surrogate markers for bone health in children on HD. Within a 4-week period, at least 20–30% of measures would dictate a discrepant decision from the referent measure of that month. These findings have important implications for clinical decision-making and underscore the need to base therapeutic decisions on trends rather than single measurements.
KW - End stage kidney disease
KW - Fibroblast growth factor 23
KW - Hemodialysis
KW - Metabolic bone disease
KW - Parathyroid hormone
KW - Pediatrics
KW - Variability
UR - http://www.scopus.com/inward/record.url?scp=85021728792&partnerID=8YFLogxK
U2 - 10.1007/s00467-017-3730-4
DO - 10.1007/s00467-017-3730-4
M3 - Article
C2 - 28667458
AN - SCOPUS:85021728792
SN - 0931-041X
VL - 32
SP - 2311
EP - 2318
JO - Pediatric Nephrology
JF - Pediatric Nephrology
IS - 12
ER -