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. “We will continue to monitor the health of the study participants and will seek to determine the cause.”
Although the reason for 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 necessarily be better – and will force experts to reassess their thinking about how to treat one of the nation’s leading health problems.
“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.
“This is the second big surprise,” said Steven Nissen, a Cleveland Clinic cardiologist. “This suggests that there are things drugs do that we don’t understand. We have to really ask the question: ‘How low do you go?’ “
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, amputations, blindness and increased risk for heart attacks and strokes.
Many earlier studies had shown that tightly controlling blood sugar significantly reduced the risk for many complications. The new study trial was designed to convincingly test whether various aggressive treatment strategies reduce the risk for heart disease – the main cause of death among diabetics.