Fasting plasma C-peptide and micro- and macrovascular complications in a large clinic-based cohort of type 1 diabetic patients.
OBJECTIVE
A protective effect of residual beta-cell function on microvascular complications of type 1 diabetes has been suggested. Our aim was to retrospectively evaluate the association of fasting plasma C-peptide values with micro- and macrovascular complications.


METHODS
We recruited a clinic-based cohort of 471 type 1 diabetic patients born after 1945 and cared for in the period 1994-2004. Centralized measurements and standardized procedures of ascertainment of micro- and macrovascular complications were employed. Individual cumulative averages of A1C up to 2007 were calculated.


RESULTS
Residual beta-cell secretion was detected even many years after diabetes diagnosis. In multivariate linear regression analysis, fasting plasma C-peptide values were positively associated with age at diagnosis (beta = 0.02; P < 0.0001) and triglycerides (beta = 0.20; P = 0.05) and inversely associated with diabetes duration (beta = -0.03; P < 0.0001) and HDL cholesterol (beta = -0.006; P = 0.03). The final model explained 21% of fasting C-peptide variability. With respect to fasting C-peptide values in the lowest tertile (<0.06 nmol/l), higher values were associated with lower prevalence of microvascular complications (odds ratio [OR] 0.59 [95% CI 0.37-0.94]) independently of age, sex, diabetes duration, individual cumulative A1C average during the study period, hypertension, and cardiovascular diseases. No association was evident with macrovascular complications (0.77 [0.38-1.58]).


CONCLUSIONS
Our study shows an independent protective effect of residual beta-cell function on the development of microvascular complications in type 1 diabetes, suggesting the potential beneficial effect of treatment that allows the preservation of even modest beta-cell function over time.
Panero
Francesco
F
Department of Internal Medicine, University of Turin, Turin, Italy.
Novelli
Giulia
G
Zucco
Chiara
C
Fornengo
Paolo
P
Perotto
Massimo
M
Segre
Olivia
O
Grassi
Giorgio
G
Cavallo-Perin
Paolo
P
Bruno
Graziella
G
D000328:Adult; D017668:Age of Onset; D001794:Blood Pressure; D015992:Body Mass Index; D002096:C-Peptide / Q000097:blood*; D002318:Cardiovascular Diseases / Q000453:epidemiology; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000150:complications* / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000453:epidemiology*; D003928:Diabetic Nephropathies / Q000453:epidemiology; D003929:Diabetic Neuropathies / Q000453:epidemiology; D005215:Fasting; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D050417:Insulin-Secreting Cells / Q000378:metabolism; D007558:Italy; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D012044:Regression Analysis
D002096:C-Peptide