WASHINGTON — Aggressively driving blood- sugar levels as low as possible in high-risk diabetes patients appears to increase the risk of dying from a heart attack or stroke, according to a major government study that stunned and disappointed experts.
The startling discovery, announced Wednesday, prompted federal health officials to immediately halt one part of the massive trial so thousands of the type 2 diabetes patients in the study could be notified and switched to less intensive, less risky treatment.
“As always, our primary concern is to protect the safety of our study volunteers,” said Elizabeth G. Nabel, director of the National Heart, Lung and Blood Institute, which is sponsoring the study.
Although the reason for the increased risk remains a mystery, Nabel and other experts stressed that the benefits of blood-sugar control have been well-established for diabetics and that patients should not make any changes in their care without consulting their doctors.
But the findings cast doubt on a major assumption about diabetes treatment — that pushing levels as close to normal as possible would be better — and will force experts to reassess their thinking about how to treat one of the nation’s leading health problems.
Diet, exercise and medication
“It’s profoundly disappointing,” said Richard Kahn, chief scientific and medical officer for the American Diabetes Association. “This presents a real dilemma to patients and their physicians. How intensive should treatment be? We just don’t know.”
The findings are the second major blow to fundamental assumptions about how to protect against heart disease — the nation’s leading killer. Another recent major study found that driving blood cholesterol levels as low as possible did not necessarily slow the progression of heart disease.
An estimated 21 million Americans suffer from type 2 diabetes, the most common form of the disease, and the number has been increasing because of the obesity epidemic. Diabetes patients’ blood-sugar levels rise abnormally high, causing a host of serious complications, including nerve damage, blindness, increased risk for heart attacks and strokes, and a need for amputations.
Many earlier studies had shown that tightly controlling blood sugar significantly reduced the risk for many complications. The new study, known as the Action to Control Cardiovascular Risk in Diabetes, or ACCORD, trial was designed to convincingly test whether various aggressive treatment strategies reduce the risk for heart disease — the main cause of death among diabetics.
The study involves 10,251 type 2 diabetes patients ages 40 to 82 at 77 sites in the United States and Canada at high risk for heart disease for any reason, such as having high blood pressure, high cholesterol or being obese. About half the patients were placed on an regimen combining diet and exercise with drugs designed to lower their blood-sugar levels to that of the average person with diabetes, while the other half was put on a more intensive regimen designed to drive it closer to that of someone without diabetes. The patients were also divided further into those who also received blood-pressure-lowering medication or drugs to improve their cholesterol levels.
Special panel monitored study
After about four years, about half of the participants in the intensive treatment group achieved blood-sugar levels close to normal and about half the patients in the standard treatment group achieved levels close to the average diabetic.
But a special 10-member panel that was monitoring the study alerted the organizers that 257 patients receiving the intensive treatment had died, compared with 203 receiving standard treatment, a difference of 54 deaths — or 3 per 1,000 participants, officials said. About half the excess deaths were from heart disease.
“We obviously were surprised,” Nabel said. “We were hoping for a positive outcome.”
