Feb. 10, 2000 (Tuscaloosa, Ala.) -- Doctors and patients with diabetes who aggressively treat and maintain near-normal blood sugars received good news on Wednesday with the release of a study showing that this intensive treatment leads to long-lasting benefits with significantly less eye and kidney disease.
Blindness and kidney failure are two common complications of diabetes, especially when the blood sugar, or glucose, is out of control. Type 1 diabetes, which occurs most commonly in children and young adults, is treated with daily injections of insulin. Type 2 diabetes, which is far more common, is usually diagnosed in adults over 40 and is treated with pills and/or insulin.
The current study, which is a follow-up of a previous study done on type 1 diabetics who were treated with intensive therapy four years earlier, consisted of more than 1,200 people with type 1 diabetes, aged 13 to 39, who were generally in good health. This study was designed to compare how well diabetics do on "conventional" vs. "intensive" therapy in the long-term. The current results, which are published in this week's issue of The New England Journal of Medicine, are the preliminary findings after four years of following these patients.
In the previous study, the patients received either conventional therapy, which consisted of one to two insulin injections per day with one urine or blood glucose test per day. The intensive therapy group consisted of at least three daily insulin injections or treatment with an insulin pump, with frequent adjustments in the dose of insulin on the basis of blood glucose levels, which were checked at least four times a day. This group was also kept on a strict diet and enrolled in an exercise program.
At the end of the initial study, patients in the conventional therapy group were offered instruction on how to do intensive therapy. "Once they understood the importance of what we had discovered, most of the conventionally treated patients took advantage of the opportunity to begin intensive therapy, and so they were enrolled in the follow-up study known as the Epidemiology of Diabetes Interventions and Complications [EDIC] trial," David M. Nathan, MD, one of the study's lead investigators, tells WebMD.
"[We found] that the beneficial effects of intensive therapy to control blood sugar levels persists after four years even though the [HbA1C] levels of the intensively treated patients tended to drift upward," says Nathan, a professor of medicine at Harvard University. HbA1C is a blood test that indicates how well diabetics have been able to control their blood sugar levels over the previous two to three months.
The new finding is exciting information, say two diabetes specialists asked for objective assessments of the study.
"The good news is even better than we thought," says Daniel Einhorn, MD. "The benefits of intensive blood sugar control extend out over time. According to the article, patients in the original study who were under conventional treatment are doing better now under intensive therapy, and the patients in the intensively-treated group that did great in the original study are still enjoying the benefits of their intensive therapy head start. Both groups are doing better than they were before either of the studies."
Adds George Daily, MD, "This is additional, very strong evidence of the benefits of good blood sugar control. It emphasizes the importance of achieving tight control of blood glucose levels as early as possible."
In the current study, the proportion of patients who had worsening eye disease was lower in the original intensive-therapy group than in the group of patients formerly treated by conventional therapy. After four year of follow-up, 49% of the patients who had originally been on conventional-therapy had evidence of the beginnings of eye disease compared to only 18% of those who had been in the original group that received intensive therapy.
The proportion of patients with an increase in early signs of kidney disease was also significantly lower in the original intensive-therapy group, says Nathan. By the third or fourth year of the EDIC study, signs of early kidney disease were detected for the first time in 11% of the individuals who had been under conventional therapy, compared with only 5% of the patients in the original intensive-therapy group.
"These types of continuing risk reductions are truly spectacular," Daily tells WebMD. "These results not only confirm the value of intensive therapy, but also emphasize the benefits patients can gain by starting intensive control as early as possible." Daily is head of the division of diabetes and endocrinology at the Scripps Clinic in La Jolla, Calif.
In a way, says Einhorn, that finding is reassuring. "One of the criticisms of the original study was that it was not real life -- that people with diabetes who weren't getting special attention from researchers and diabetes educators couldn't maintain intensive therapy with the many insulin injections and self-applied finger sticks to test blood sugar levels that are necessary."
"However, this was a real-world study," continues Einhorn, an associate clinical professor of medicine at the University of California, San Diego, "These patients were under the care of their own physicians, but weren't getting extra attention from study coordinators."
"Even though the patients who remained on intensive therapy weren't able to maintain quite the same level of glucose self-monitoring that they had achieved during the original study, they were able to test their sugar levels frequently enough to maintain pretty good control," points out Einhorn. "And the group of patients who switched to intensive control were able to maintain blood sugar control for long enough to lower their HbA1C levels. That indicates that if they go on intensive therapy, other diabetic patients who are on insulin can achieve the same results, and reap the benefits, even type 2 patients who require insulin."