Insulin versus insulin plus sulfonylureas in type 2 diabetic patients with secondary failure to sulfonylureas.

According to the modern pathophysiological understanding of type 2 diabetes and the mechanisms of sulfonylurea action, combined insulin-sulfonylurea therapy appears to be an interesting alternative for treating diabetic patients with secondary failure to sulfonylureas. From its revival in the early 1980s, combination therapy has been shown to have a positive effect on blood glucose control although initially published clinical studies, generally open and uncontrolled, have been widely criticized. Several recent well-designed studies confirmed these favorable results, with better glucose profiles and/or decreased insulin needs, which were shown to persist after 1 year or more. Most of the studies investigating the mechanism of action indicate that the effect is mainly due to stimulation of the residual insulin secretion with minimal or no effect on insulin sensitivity. The risk of hypoglycemic episodes is rather small when insulin doses are adapted at the beginning of the combined therapy. Effects on lipid metabolism are minimal and controversial. Thus, insulin-sulfonylurea treatment may be a safe and effective solution in type 2 diabetic patients with secondary failure to sulfonylureas, particularly in those with significant residual endogenous insulin secretion. The additional cost of such combined therapy should be weighed against the potential advantages of better metabolic control.