Effects of insulin versus sulphonylurea on beta-cell secretion in recently diagnosed type 2 diabetes patients: a 6-year follow-up study.

BACKGROUND

Early insulin treatment is considered more beneficial than anti-diabetic medication with sulphonylureas, because the latter may exert negative effects on beta-cell function, while the former may help preserve it. In a previous study, we found that C-peptide response was increased in the insulin-treated group, whereas it was decreased in the glibenclamide group. However, it was not certain whether the advantage remained in the longer term.

AIM

In this study, we tested whether early insulin treatment is more beneficial than glibenclamide against a 6-year follow-up perspective.

METHODS

We designed a randomized clinical trial in subjects with newly diagnosed type 2 diabetes. Glucagon stimulatory tests, measuring C-peptide and islet amyloid polypeptide (IAPP), were performed after 2, and 3, days of temporary insulin and glibenclamide withdrawal.

RESULTS

18 subjects initially randomized to glibenclamide, and 16 randomized to two daily injections of insulin, participated in end-of-study investigations. C-peptide response to glucagon deteriorated (p < 0.01 vs. baseline) in initially glibenclamide-treated patients (n = 18), but not in insulin-treated patients (p < 0.05 for difference between groups, after 2 days of treatment withdrawal). The IAPP response to glucagon declined in the glibenclamide group (p < 0.001), but not in insulin-treated subjects (p = 0.05 for difference between groups).

CONCLUSIONS

Early insulin treatment preserves beta-cell secretory function better than glibenclamide even in a 6-year perspective.