Abstract

BACKGROUND
This study was undertaken to observe the changes of basal C-peptide level and to compare the clinical and immunogenetic characteristics in newly dignosed young age-onset diabetics in Korea. We studied predictors effecting the change of insulin secretory capacity in these patients. METHODS: 82 newly diagnosed young diabetic patients (mean age; 23.0+7.1, M:F=46:36) were divided into 3 groups according to the initial fasting serum C-peptide level (Classification I, group 1; C-peptide < 0.6 ng/mL, group 2; 0.6 ng/mL C-peptide <1.2 ng/mL, and group 3; 1.2 ng/mL C-peptide) and reclassified by the follow-up (mean follow-up; 3.7 year) fasting serum C-peptide level. RESULTS: According to the initial fasting serum C-peptide level, 17.1% (14/82) of the patients were classified as group 1, 35.4% (29/82) as group 2, and 47.5%(39/82) as group 3. In group 3, body mass index (BMI, p<0.01) and maximal BMI (p<0.01) at onset, family history of diabetes (p=0.01) and stimulated C-peptide increment were significantly higher than those in group 1 and 2. Presence of urine ketone (p<0.01), history of diabetic keto- acidosis (p<0.01), and frequency of insulin therapy at diagnosis (p<0.01) were significantly lower than those in group 1 and 2. No significant differences in onset age, sex, weight loss at onset, HbA1c, anti GAD antibody and HLA-DR were found among the 3 groups. After certain follow-up periods, 37.8% (31/82) of the patients were reclassified as group 1, 24.4% (20/82) as group 2, and 37.8% (31/82) as group 3 according to the follow-up fasting serum C-peptide level(classification II). All of the patients in group 1 in classification I were reclassified as group 1 in classification II. In group 2, 44.8% were reclassified as group 1 and 17.3% were reclassified in group 3. In group 3, 15.4% (6/39) of patients showed a significant decrease in insulin secretory capacity and were reclassified as type I diabetes, and their predictors for decreased insulin secretory capacity were low BMI at onset, low slimulated C-peptide increment, and antiGAD antibody. CONCLUSION: Our study showed that classification of newly diagnosed young diabetics by fasting C-peptide level is not always easy. Therefore follow-up measurement of C-peptide and consideration of clinical characteristics are needed in discriminating the type of diabetes in these groups of diabetics in Korea.

• Keywords: Key Words;Young age onset diabetics;C-peptide;Follow-up study;