Progression of microvascular disease in patients with diabetes can result in blindness and renal failure. Intensive glycemic control is important in patients with insulin-dependent (type 1) diabetes mellitus to reduce the risk of complications associated with microvascular disease. These problems affect patients with non–insulin-dependent (type 2) diabetes less frequently, so the benefits of tight control in this patient group are less convincing. Vijan and associates created a model to calculate the risks associated with development of blindness and end-stage renal disease in patients at different ages of diabetes onset and for levels of glycemic control.
Patients were assumed to have no clinically detectable complications of microvascular disease at the time of diagnosis. Patients with complications at the time of diagnosis are at high risk, and intensive glycemic control should be considered. The risks for end-stage outcomes are highest in patients who are diagnosed with diabetes at a young age and in those who have poor glycemic control.
In patients with type 2 diabetes, the risks of complications and the benefits of increased glycemic control are less clear. Improving glycemic control reduces the risk of microvascular complications in patients who are diagnosed with type 2 diabetes at a young age, and tight glycemic control is indicated for these patients. However, definitive evidence that moderate glycemic control provides much benefit to patients diagnosed with type 2 diabetes later is lacking.
The authors conclude that their model adequately estimates which patients are most likely to benefit from intensified glycemic control. Those with late-onset diabetes benefit less from intensified glycemic control, although in some cases, because of high short-term risk and potential benefit, interventions in older patients have as much or more value as interventions in younger patients. Targeting specific patients who are at high risk is likely to achieve the most benefit.
In an editorial in the same issue, Skyler notes that the evidence supporting tight glycemic control for patients with type 1 diabetes should be generalized to those with type 2 diabetes, citing that the American Diabetes Association Standards of Care recommend striving for tight glycemic control in all patients with diabetes. He points out that the use of simulation models, such as that used by Vijan and associates, are theoretic and require validation. However, he concedes that elderly patients with type 2 disease may not need treatment as aggressive as that required in younger patients. He calls for more research so that treatment programs may be developed that focus on improved glycemic control for all patients with diabetes.
editor's note: The debate about the value of tight glycemic control in patients with type 2 diabetes continues. Some evidence indicates that maintaining euglycemia through diet, exercise and medication delays vascular complications, depending on individual characteristics such as age and the presence or absence of microvascular disease at the time of diagnosis. Problems such as hypoglycemia and poor patient compliance make individualization of glycemia goals critical in these patients, even with the current recommendations of the American Diabetes Association. One specific recommendation for all patients may not be appropriate at this time.—r.s.