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Clinical Significance of Urinary C‐Peptide Excretion in Children with Insulin‐Dependent Diabetes Mellitus
Author(s) -
HUTTUNEN N.P.,
KNIP M.,
KÄÄR M.L.,
PUUKKA R.,
ÅKERBLOM H. K.
Publication year - 1989
Publication title -
acta pædiatrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 115
eISSN - 1651-2227
pISSN - 0803-5253
DOI - 10.1111/j.1651-2227.1989.tb11069.x
Subject(s) - excretion , medicine , endocrinology , diabetes mellitus , c peptide , albuminuria , urine , urinary system , postprandial , renal function
ABSTRACT. In order to evaluate the accuracy of urinary C‐peptide determination and the clinical significance of C‐peptiduria for the early course of insulin‐dependent diabetes (IDDM), the rate of urinary excretion of C‐peptide was determined in 32 children and adolescents with IDDM and correlated with serum C‐peptide concentration, urinary excretion of albumin and β‐mic‐rogloublin and with the glomerular filtration rate (GFR) measured in terms of the clearance of 99 mTc‐DTPA. The age of the subjects ranged from 9.1 to 17.1 years (mean 13.1) and the duration of diabetes from 0.3 to 11.9 years (mean 4.6). There was a good correlation between postprandial serum C‐peptide concentration and the 24‐hour urinary C‐peptide excretion rate ( r =0.81; p <0.001). GFR and urinary albumin excretion were slightly elevated in the diabetic patients as compared with non‐diabetic subjects ( p <0.05 and p <0.001, respectively), but C‐peptide excretion was unrelated to the degree of hyperfiltration or albuminuria, neither was there any correlation between the excretion rate of β 2 ‐microglobulin and C‐peptide. Glycaemic control was poorer in the diabetic children who had only trace amounts of C‐peptide in their urine (<0.05 nmol/m 2 /24 h) than in those with minimal (0.05–1.0 nmol/m 2 ) or moderate 24‐hour urinary C‐peptide excretion (>1.0 nmol/m 2 ). It is concluded that urinary C‐peptide excretion serves very well to reflect residual β‐cell function and is unrelated to the slight renal hyperfunction and albuminuria often seen in diabetic subjects. Even minimal C‐peptide excretion ranging from 0.05 to 1.0 nmol/m 2 /24 h still seems to indicate clinically significant insulin secretion.