By George Ochoa
The Data and Safety Monitoring Board (DSMB) of the National Institutes of Health has recommended that the intervention arm of the Look AHEAD (Action for Health in Diabetes) study be discontinued because it showed that an intensive diet and exercise intervention program, resulting in moderate weight loss, did not reduce major cardiovascular events in overweight and obese adults with type 2 diabetes.
However, the board encouraged the study, which it funds, to follow all Look AHEAD participants to identify longer-term effects of the intervention.
Half of the 5,145 participants in the multicenter study were randomly assigned to the intensive lifestyle intervention arm and the other half to a general program of diabetes support and education, according to the news release. Both study arms received routine medical care by their health care providers. The primary outcome of the study was to measure the aggregate occurrence of major cardiovascular events, including cardiovascular death (such as fatal myocardial infarction and stroke), nonfatal myocardial infarction and stroke, and hospitalized angina.
“Cardiovascular morbidity and mortality—that was the important question,” said Rena Wing, PhD, professor of psychiatry, Alpert Medical School, Brown University, Providence, R.I., and chairwoman of the Look AHEAD study. The study was unique, she said, “in the sense that it was the first randomized trial to see if an intensive lifestyle intervention that resulted in weight loss in individuals with type 2 diabetes would actually help reduce the risk for cardiovascular morbidity and mortality. Patients were followed for up to 11<00BD> years.”
Lee M. Kaplan, MD, PhD, director, Obesity, Metabolism, and Nutrition Institute at Massachusetts General Hospital in Boston, who is not associated with the Look AHEAD study, said in an interview: “Long-term cardiovascular outcomes … are the areas of the greatest risk and danger to patients—the outcomes that can kill you. This study looked at these outcomes with sufficient power to find a difference between study groups, if it had existed.”
Dr. Wing said that the DSMB “concluded that the study had reached its answer. There were no differences between the two groups in the number of participants with cardiovascular morbidity and mortality. The odds that a difference would be detected were very slight at this point.”
However, she noted, “Both study arms had a much lower risk for developing heart disease than we expected. In both groups, these patients with type 2 diabetes were getting good medical management. Possibly this helped to reduce the risk.”
The intensive lifestyle intervention did bring health benefits, Dr. Wing reported. “There were fewer symptoms of depression, less use of diabetes medication, better blood sugar control and improved sleep apnea. The level of physical functioning was better maintained. I would think for most patients it’s important to recommend lifestyle intervention because of better quality of life.”
Patients in the intervention arm lost 9% of their body weight initially (almost 20 pounds), and maintained a reduction of 5% of body weight through the end of the trial (about 10 pounds), said
Asked whether the Look AHEAD trial had implications for bariatric surgery as an alternative method of weight loss, Dr. Wing said, “Bariatric surgery produces larger weight loss. But there has not yet been a real randomized trial to see if it will reduce cardiovascular morbidity and mortality.”