Early tight control reduces long-term complications
Eye, kidney complications curtailed in Type 1
There’s another reason to add tight control to your list of prevention-based measures. The latest analysis of the Diabetes Control and Com-plication Trial (DCCT) shows dramatic long-term reductions in microvascular complications for patients who undergo intensive therapy early in their disease.
The results provide strong support for beginning intensive therapy as early as possible in the course of Type 1 diabetes and maintaining it for as long as possible, says a DCCT research group in a paper published Feb. 10 in the New England Journal of Medicine.
"The results probably apply to Type 2 diabetes as well, although there are no comparable data available yet," says lead researcher David Nathan, MD, an endocrinologist and professor of medicine at Harvard Medical School and director of Massa-chusetts General Hospital’s Diabetes Center in Boston.
His team found that even though blood sugars crept up over the years after the trial ended, Type 1 patients who began receiving intensive therapy at the time of diagnosis had a 71% lower risk of developing early microvascular complications over an average of 6.5 years than those in the conventional therapy group.
"This doesn’t mean that intensive therapy should be short-term," says Nathan. "What it means is that early efforts to get sugars under control pay off in the long run."
The DCCT intensive therapy group got at least three daily injections of insulin or treatment with an insulin pump, with the dose adjusted frequently on the basis of self-monitored blood glucose values and diet and exercise. Conventional therapy consisted of one or two insulin injections per day with one urine or blood test each day.
At the end of the DCCT, all patients were offered intensive therapy supervised by their own physicians. Nearly all patients in the former intensive therapy group and 75% of the patients in the former conventional therapy group were treated intensively throughout the follow-up Epidemiology of Diabetes Interventions and Complication (EDIC) study.
Researchers evaluated retinopathy on the basis of centrally graded fundus photographs in 1997, four years after the DCCT ended and they measured nephropathy on the basis of urine specimens during the third or fourth year after the DCCT ended. The conventional therapy group had nearly twice the incidence of microalbuminuria as the tight control group had.
Those on initial tight control had a 53% lower risk of mild kidney disease and an 83% lower risk of severe kidney disease. Forty-nine percent of the conventional therapy group had a progression in retinopathy of three steps or more from baseline, while 18% of the tight control group had deteriorated that far. With adjustments for levels of retinopathy at the end of the DCCT, researchers projected a 75% reduction in the likelihood of progression with early tight control.
At the time of enrollment, the mean HbA1c in each group was about 9%. During the 6.5 years of follow-up, patients in the intensive therapy group had a median HbA1c of 7.2%, and the conventional therapy group’s was 9.1%. However, during the EDIC, the two groups’ values had almost converged at a median value of 8.1% for conventional therapy and 7.7% for the intensive group.
Nathan says those results demonstrate the value of early control since the microvascular co-morbidity rates of the two groups remain very different. "This suggests that while there is clearly a momentum to complications, once there is a benefit, it remains a benefit."
He notes there was a high level of compliance among all patients in the DCCT and EDIC — 98% in the intensive therapy group and 97% in the conventional therapy group. "This was a highly motivated group of volunteers. They were carefully selected and had a high level of education. It’s also important to remember that 15% of the participants were adolescents, and that’s a group that generally has difficulty with adherence."
To clinicians, the DCCT and EDIC are particularly important because this group of patients and their physicians did not have the benefit of knowing all their hard work would pay off, Nathan says.
"For patients now, this should be a tremendous motivator, to know that they can get a 50% to 75% reduction in the instance of loss of vision by intensive therapy at the outset," he says. "Even if they can’t get their HbA1c [levels] down to 6% or give themselves four insulin shots a day, the lower they keep their average glucose levels, the better chance they stand against complications. It is not an all-or-none phenomenon. If they do the best they can, they’ll get positive results."
Clinicians should be "cheerleaders" for their patients, he says. "Every patient needs to be treated uniquely and individually. Find out what works for that individual patient, and you’ll have the key to his successful treatment."
Follow-up is always a problem
In the real world of diabetes treatment, follow-up is always going to be a problem, both in terms of patients’ time and in terms of cost, says Barbara Schreiner, RN, MN, CDE, associate director of the diabetes care center at Texas Children’s Hospital in Houston.
Nathan’s group’s findings are not really surprising, especially in terms of the control "flip" that took place after the DCCT ended, she says. "What happened? Life got in the way. They weren’t so intensively involved and didn’t have to talk to someone on the diabetes care team every week."
After an initial period of intensive control, the presence of a support team is essential to long-term diabetes management, Schreiner says.
Texas Children’s Hospital continues to provide telephone follow-up even though insurers refuse to pay for it. "We’ve just stopped charging for the phone contacts," she says. "Our institution decided it was worth it to continue, but managed care’s attitude from a financial standpoint is that they question whether it should cost $1,000 or $5,000 to help a patient lower his HbA1c by 1%."
While there is voluminous evidence to support the cause for tight control over the long term, managed care has not yet acknowledged the short-term benefits, although at least one study has demonstrated clear short-term dollar savings, Schreiner says. The person-to-person contact is clearly a boon to patients struggling with the ongoing challenges of their disease, but she suggests that interactive Web sites and chat rooms may serve some of the same purposes at a lower cost. Ongoing support groups are also helpful.
[Contact David Nathan at (617) 726-2873 and Barbara Schreiner at (713) 770-1000.]
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