One of the biggest concerns for patients with Type 1 diabetes has always been long-term microvascular complications-blindness caused by retinopathy, renal failure caused by nephropathy, and nerve damage caused by neuropathy. In 1993, the Diabetes Control and Complications Trial showed that more frequent insulin injections could better control glucose levels and slow the progression of these complications. During this 10-year, randomized, controlled study, researchers followed 1,441 people with Type 1 diabetes. The study compared the effects of intensive insulin therapy and conventional insulin therapy on the development and progression of early microvascular complications. People in the control group received the standard treatment of one or two injections of insulin every day. Those in the other group received three or more injections of insulin every day. The results were clear: Intensive therapy does a better job of keeping blood glucose levels as close to normal as possible, which reduces the risk of retinopathy, nephropathy, and neuropathy by about 60%.

Research since this study has shown that most adults and adolescents with Type 1 diabetes can benefit from intensive insulin therapy. In patients with Type 2 diabetes, however, the intensive therapy may exacerbate macrovascular complications, canceling out any benefit.

A patient who uses intensive insulin therapy needs to know that she must rigorously monitor her blood glucose levels and frequently adjust her insulin dose. Doses should change when blood glucose levels fluctuate, when the patient alters her diet or exercise routine, and when she's sick. Be aware that for some patients the expense of intensive therapy may be a burden. Frequent blood glucose monitoring requires more test strips, and the patient must make more visits to her physician, dietitian, and nurse educator.