Losing weight — an average of 5% of total body weight — `and keeping it off for 4 years didn’t reduce the number of heart attacks or strokes in persons with diabetes.
That result prompted the National Heart, Lung, and Blood Institute to pull the plug on its massive Look AHEAD (Action for Health in Diabetes) study.
The study enrolled 5,145 people with type 2 diabetes and a BMI greater than 25, randomizing half to a lifestyle intervention and half to a general program of diabetes support and education.
Although those in the intervention group kept off 5% of their initial body weight at 4 years, there was no difference between them and the standard care group in the rate of myocardial infarction, stroke, hospitalizations for angina, and cardiovascular death — the primary outcome.
Essentially, there was no harm from the intervention, but there was no benefit either, according to a statement from the NIH.
Because of the finding of futility, the study’s data and safety monitoring board recommended the trial be stopped.
Mary Evans, MD, director of special projects in nutrition, obesity, and digestive diseases at the National Institute of Diabetes and Digestive and Kidney Diseases, told MedPage Today that people who “volunteer for a weight-loss intervention study involving reductions in calorie intake and increased physical activity may be healthier than the general population with type 2 diabetes.”
She said that participants had to pass a treadmill test to assure it was safe for them to exercise. They also received annual feedback about their risk factors, including HbA1c, blood pressure, and cholesterol levels.
After the first year, Look AHEAD participants in the lifestyle intervention arm had lost 10% of their initial body weight, but as time went on, they gained some of it back. The standard care group lost about 1% of its initial body weight at both 1 and 4 years.
Despite no reduction in cardiovascular events in those in the intense intervention arm, they did experience other health benefits. Patients in this group saw improvements in sleep apnea and mobility, as well as quality of life. In addition, their diabetes medications were reduced.
In addition, at 1 and 4 years, both diabetes control (glucose, HbA1c) and most cardiovascular disease risk factors (blood pressure, HDL cholesterol, triglycerides) were more favorable in the lifestyle intervention than in the control group with the exception of LDL cholesterol, which was not different between groups at year 1, Evans shared.
At year 4, those in the intensive lifestyle intervention group continued to have more favorable diabetes control and CVD risk factor reduction, with the exception of LDL-C in which there were slightly greater reductions in the standard care group. Participants in the lifestyle intervention group maintained greater improvements in fitness at both years 1 and 4, Evans said.
To be enrolled, patients had to have their blood pressure under at least moderate control (160/100 mmHg), HbA1c levels ≤11%, and fasting triglycerides concentration less than 600 mg/dL. The trial included those with and without a history of cardiovascular disease.
“Cardiovascular event rates in diabetic individuals with heart disease are expected to be approximately twice those of diabetic individuals without a history of heart disease,” according to the study protocol.
The ages of participants ranged from 45 to 76, and 60% were women.
“Data from the end of the study are currently being analyzed to better understand the relationship between changes in fitness, weight, diabetes control, cardiovascular disease risk factor control, and outcomes in the Look AHEAD study,” Evans said.
Researchers also are exploring differences in subgroups, such as minorities (about 37% of the total population) and those with a history of cardiovascular disease.