Rates of serious complications drop with intensive therapy, study shows
MONDAY, July 27 (HealthDay News) -- By carefully controlling blood sugar levels and taking medications that lower blood pressure and cholesterol, people with type 1 diabetes can significantly reduce their risk of developing the most serious complications associated with the disease, new research shows.
In a study appearing in the July 27 issue of the Archives of Internal Medicine, scientists report that people who intensively manage their blood sugar levels have less than a 1 percent chance of becoming blind, needing a kidney transplant or losing a limb.
"We wanted to describe what happens with modern day management, and over a 30-year period, we found that people with type 1 diabetes should no longer be suffering from those most serious complications," said study co-author Dr. Daniel Nathan, director of the diabetes center at Massachusetts General Hospital and a professor of medicine at Harvard Medical School in Boston.
"This study provides a good motivational message," said Nathan, who added that with good blood glucose control, "type 1 diabetes need not be accompanied by the frequent occurrence of long-term complications, and people with type 1 diabetes can look forward to long, healthy, productive lives."
Barbara Araneo, director of diabetic complications for the Juvenile Diabetes Research Foundation, called the study results "fantastic." She credited recent improvements in care on good blood glucose management plus a greater awareness of the need for controlling blood pressure and cholesterol levels in people with type 1 diabetes. "A lot of people key into the [blood sugar control] number, but we really need to look at it systemically," she said.
The current study is a continuation of previous work and included 1,441 people enrolled in the Diabetes Control and Complications Trial (DCCT), as well as 161 people from the Pittsburgh Epidemiology of Diabetes Complications (EDC) study. The average time since the diagnosis of type 1 diabetes was 25 to 30 years.
At the time both of these studies started in the 1980s, conventional type 1 diabetes management was significantly different than it is today. Home blood glucose meters had only recently been introduced, and there were fewer options in insulin and insulin delivery at the time.
The DCCT trial was an intervention trial, and half of the volunteers were asked to take more frequent insulin and monitor their blood sugar levels more often with the goal of achieving a hemoglobin A1c (HbA1c) level of around 6 percent. The conventional group had levels of about 9 percent at the end of the study, while the intensive group had lowered their A1c levels to an average of 7.4 percent. Hemoglobin A1c is a test that measures blood sugar control over the past two to three months. A normal level for someone without diabetes is less than 6 percent. Forty-four percent of those in the intensive arm of the DCCT had HbA1c levels of less than 7 percent.
The EDC trial was simply an observational trial, and no intervention above normal management was given. Their average HbA1c levels at the end of the study were 7.8 percent.
After almost 30 years of having diabetes, the cumulative incidence of diabetic eye disease was 50 percent in the DCCT's conventional treatment group, 47 percent in the EDC group and 21 percent in the intensive-management group.
Diabetic kidney disease was present in 25 percent of those in the standard DCCT group, 17 percent in EDC and just 9 percent in the intensive DCCT group.
Heart disease occurred in 14 percent of the conventional group and EDC, and 9 percent in the intensively managed DCCT volunteers. However, it should be noted that the study participants were, on average, only in their 30s and 40s when these studies ended.
Both Nathan and Araneo said that with the improved management tools available today, these results will likely be even better in the future.
Both also pointed out that lower HbA1c levels can cause another serious complication -- low blood sugar (hypoglycemia). Severe hypoglycemia that resulted in either a coma or seizure occurred in 16 percent of the DCCT intensive management group, and between 10 percent and 20 percent of the EDC group. Araneo said that better and more frequent blood glucose monitoring has likely reduced the number of severe episodes, but a lack of awareness of hypoglycemia and hypoglycemia remain big problems.
The bottom line, she said, "is that there's always something you can do about diabetes. It's not hopeless. There's better management now than ever, and with continued research there will be better management in the future. There's excellent hope that someone with type 1 diabetes won't suffer the health decline associated with diabetes complications."
Learn more about type 1 diabetes from the Nemours Foundation's KidsHealth.
SOURCES: David Nathan, M.D., director, diabetes center, Massachussetts General Hospital, and professor, medicine, Harvard Medical School, Boston; Barbara Araneo, Ph.D., director, diabetic complications, Juvenile Diabetes Research Foundation, New York City; July 27, 2009, Archives of Internal Medicine
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