Metabolic factors affecting residual beta cell function assessed by C-peptide secretion in patients with newly diagnosed type 1 diabetes.
BACKGROUND
In recent onset of type 1 diabetes, the residual beta cell function, assessed by baseline and/or stimulated C-peptide secretion, can be a useful parameter to establish the extension of beta cell destruction. How metabolic parameters at diagnosis influence residual C-peptide secretion is not well established.


METHODS
We analyzed 553 consecutive patients with recent onset (<4 weeks) of type 1 diabetes (250 females and 303 males, mean age 15+/-8 years). Baseline and stimulated C-peptide by i.v. glucagon were evaluated using a highly sensitive radio-immunoassay. Metabolic parameters including blood glucose, HbA1c, insulin dose, and BMI were also evaluated.


RESULTS
Baseline and stimulated C-peptide were 0.26+/-0.22 and 0.47+/-0.38 nmol/l and correlated positively with age (p<0.001). There was no significant correlation between C-peptide and blood glucose at diagnosis. BMI was positively correlated with both baseline and stimulated C-peptide secretion (p<0.001). By contrast, HbA1c levels inversely correlated with both baseline and stimulated C-peptide secretion (p<0.001).


CONCLUSIONS
In type 1 diabetes at diagnosis, baseline and stimulated C-peptide are higher in pubertal and young adult patients compared with pre-pubertal patients suggesting that such parameter can be used as an end point marker for studies aimed at protecting and/or restoring beta cells in patients with substantial beta cell function. High levels of HbA1c and lower BMI are dependent variables of C-peptide values.
Picardi
A
A
Department of Endocrinology and Diabetes, University Campus Bio-Medico, Via E. Longoni 83, 00155 Rome, Italy.
Visalli
N
N
Lauria
A
A
Suraci
C
C
Buzzetti
R
R
Merola
M K
MK
Manfrini
S
S
Guglielmi
C
C
Gentilucci
U V
UV
Pitocco
D
D
Crinò
A
A
Bizzarri
C
C
Cappa
M
M
Pozzilli
P
P
D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood*; D015992:Body Mass Index; D002096:C-Peptide / Q000097:blood* / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000175:diagnosis* / Q000188:drug therapy; D042241:Early Diagnosis; D005260:Female; D005934:Glucagon; D006442:Glycated Hemoglobin / Q000378:metabolism; D006728:Hormones; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage; D007328:Insulin / Q000008:administration & dosage; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008297:Male; D015999:Multivariate Analysis; D011379:Prognosis; D011863:Radioimmunoassay
D015415:Biomarkers; D002096:C-Peptide; D005934:Glucagon; D006442:Glycated Hemoglobin; D006728:Hormones; D007004:Hypoglycemic Agents; D007328:Insulin