Insulin therapy in type 2 diabetes.

OBJECTIVE: To review the increasingly common use of insulin therapy in patients with type 2 diabetes and the practical aspects of initiating insulin therapy in these patients. DATA SOURCES: Recent scientific and clinical literature identified through MEDLINE searches for the years 1995-2001 using the terms oral agents, type 2 diabetes, insulin therapy, glycemic control and diabetic complications, glucose toxicity, insulin lispro, insulin aspart, and insulin glargine. STUDY SECTION: Reports of key large (1,000 patients or more) and significant smaller, randomized, controlled clinical trials were reviewed. For studies comparing insulin analogs, the authors reviewed a sampling of the identified trials for their characteristics and clinical importance. DATA SYNTHESIS: Tight blood glucose control can help reduce the risk of diabetes complications. Evidence suggests that early insulin therapy can help correct the underlying pathogenetic abnormalities in type 2 diabetes and improve long-term glycemic control. For these reasons, some diabetes experts advocate the initiation of insulin therapy earlier in the course of type 2 diabetes than has been common in the past. Insulin regimens should be designed to mimic the body's natural physiologic secretion of insulin, including the basal amounts released continuously by the pancreas and the insulin surges produced in response to glucose loads. Using new insulin analogs is a useful approach to achieving this ideal. Insulin glargine provides a nearly constant, peakless release of insulin when injected subcutaneously once daily. Two new rapid-acting insulin analogs, insulin lispro (Humalog--Lilly) and insulin aspart (NovoLog--Novo Nordisk), enhance patients' flexibility in terms of meals by permitting injection immediately before meals, rather than 30 minutes before meals, as with regular insulin.
CONCLUSION: Patients should be reassured that early initiation of insulin therapy is a positive event that should improve their long-term health and does not represent a decline in the course of their disease.