Repaglinide has more beneficial effect on cardiovascular risk factors than glimepiride: data from meal-test study

Abstract

Aim our study is to compare the effects of repaglinide vs glimepiride administration on cardiovascular risk factors after meal test. Thus, after 2 weeks washout period, a 3-month randomised, cross-over parallel group trial of repaglinide (1 mg x 2/day) vs glimepiride (2 mg/day) in 14 patients with type 2 diabetes "naive" on diet treatment was made. Both treatments significantly declined plasma glucose, total-cholesterol, LDL-cholesterol, triglycerides, PAI-1, PAP levels and increased HDL-cholesterol. Lowering in plasma PAI-1 and PAP levels was significantly greater in repaglinide group. Furthermore, repaglinide administration resulted in a significant decrease in fasting plasma free fatty acids, fibrinogen, thrombin-antithrombin complex and reaction product of malondialdehyde with thiobarbituric acid (TBARS) levels, in absence of significant difference in fasting plasma insulin levels. Decrease in plasma TBARS levels correlated with the decrease in Plasminogen Activator Inhibitor-1 (r = 0.72; P < 0.003) and free fatty acids concentrations (r = 0.62; P < 0.01). Analysis of the insulin and glucose concentrations throughout the meal test revealed that AUC for glucose (758 +/- 19 vs 780 +/- 28 mg/Lxmin; P = 0.02) was significantly lower after repaglinide than glimepiride administration despite similar AUC for insulin (2327 +/- 269 vs 2148 +/- 292 mU/Lxmin; P = 0.105). At time 120' of meal test, repaglinide vs glimepiride administration was associated with a significant decline in plasma triglycerides, free fatty acids, fibrinogen, Plasminogen Activator Inhibitor-1, plasmin-alpha(2)-antiplasmin complex, thrombin-antithrombin complex, TBARS levels and increase in plasma HDL-cholesterol levels. In repaglinide group a negative correlation between insulin secretion during 1st phase of meal-test and plasma TBARS levels (r = -0.55; P < 0.03) at time 120' was found. Such correlation was lost after adjusting for changes in postprandial hyperglycaemia (r = -0.48; P < 0.09). In conclusion, our results support the hypothesis that repaglinide is more efficient than glimepiride on controlling for postprandial glucose excursion and may have beneficial effect on reducing cardiovascular risk factors.