ISSUES SURROUNDING TIGHT GLYCEMIC CONTROL IN PEOPLE WITH TYPE-2 DIABETES-MELLITUS

OBJECTIVE: TO review the prospective evidence surrounding the issue of tight glycemic control in people with type 2 diabetes mellitus and re sultant long-term complications. DATA SOURCE: Conference proceedings a nd a MEDLINE search (1966-February 1998) identified pertinent English- language publications on type 2 diabetes in humans. Key search terms i ncluded insulin resistance, diabetes mellitus, non-insulin-dependent, macrovascular complications, microvascular complications, and intensiv e glycemic control. STUDY SELECTION: Selection of prospective epidemio logic and clinical studies were limited to those focusing on the manag ement of type 2 diabetes. All articles with pertinent information rele vant to the scope of this article were reviewed. DATA SYNTHESIS: The p athophysiology of type 1 and type 2 diabetes differ; however, both sha re chronic complications that significantly affect morbidity and morta lity. People with type 1 diabetes have an absolute deficiency of insul in, whereas people with type 2 diabetes have varying degrees of insuli n resistance and an inadequate compensatory insulin secretory response . The Diabetes Control and Complications Trial (DCCT) has clearly indi cated that intense control of blood glucose in type 1 diabetes prevent s and slows the progression of microvascular (i.e., retinopathy, nephr opathy) and neuropathic complications. The Kumamoto study showed simil ar results in nonobese patients with type 2 diabetes. Intense insulin therapy in both populations has proven advantageous, thus supporting a common pathophysiologic process for the microvascular and neuropathic complications. Trends were seen toward fewer macrovascular (atheroscl erotic disease) complications in the intensive insulin arm of the DCCT . Conversely, trends were seen toward an increase in macrovascular com plications in the VA Cooperative study in people with type 2 diabetes using intensive insulin therapy. This may suggest a discordance in the pathophysiology of macrovascular disease between type 1 and type 2 di abetes, Additionally, it remains uncertain whether tight glycemic cont rol prevents the onset or slows the progression of macrovascular disea se, Two studies (the University Group Diabetes program and the Veteran s Affairs Cooperative Study on Glycemic Control and Complications in T ype 2 Diabetes) to date have examined pharmacotherapy options for pati ents with type 2 diabetes and resultant macrovascular complications. I t has yet to be determined whether any therapeutic intervention will d ecrease the morbidity and mortality of macrovascular disease in this p opulation. CONCLUSIONS: In type 2 diabetes, limited prospective eviden ce does support tight glycemic control to help prevent or slow the pro gression of microvascular and neuropathic complications. It is uncerta in whether tight glycemic control decreases macrovascular complication s and which pharmacotherapeutic agent(s) is/are the best options. Howe ver, therapy that improves glucose control in combination with aggress ive risk factor management should be initiated and enforced in patient s with type 2 diabetes in an effort to reduce long-term complications.