Landmark Study: Weight Loss Doesn’t Reduce Cardiovascular Event Rate in Patients With Type 2 Diabetes
Intensive lifestyle interventions are equivalent to no interventions in 11-year study (June 24)
The New England Journal of Medicine has published the results from a landmark study that investigated the long-term effects of weight loss on the risks of cardiovascular disease in patients with type 2 diabetes.
The multicenter clinical trial looked at the effects of an intensive lifestyle intervention program, intended to achieve and maintain weight loss in overweight or obese people with type 2 diabetes, on rates of cardiovascular disease. Begun in 2001, the 11-year trial enrolled 5,114 participants at U.S. clinical centers and is the longest intervention study of its type ever undertaken for patients with diabetes.
The study sought to determine whether weight loss achieved with a lifestyle program would help individuals with diabetes live longer and develop less cardiovascular disease. While short-term studies had shown that weight loss improved the control of blood sugar and mitigated risk factors for heart disease and stroke in overweight and obese individuals with type 2 diabetes, the longer-term effects of weight loss were not well studied. In particular, it was unknown whether weight loss achieved with a lifestyle intervention alone could reduce the risk of heart disease in people with type 2 diabetes.
Study participants were individuals between 45 and 75 years of age with type 2 diabetes and a body mass index (BMI) of 25 or greater. Sixty percent of the study participants were women, and 37% were from ethnic and racial minority groups.
The investigators found that weight loss in members of the study’s Intensive Lifestyle Intervention group, which was provided with a program of weight management and increased physical activity, resulted in no differences in heart attacks and strokes compared with the control group, which was provided only with general health information and social support.
The study’s primary outcome — a composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for angina — occurred in 403 patients in the intervention group and in 418 in the control group (1.83 and 1.92 events per 100 person-years, respectively; hazard ratio in the intervention group: 0.95; P = 0.51).
Speculating on the failure of weight loss to reduce the risk of cardiovascular disease, the authors suggested that even greater weight loss may be necessary to reduce cardiovascular risk in diabetes patients who are overweight or obese. They also suggested that by providing participants in both groups, and their health care providers, with annual feedback on the participants’ blood pressure, lipids, and blood sugar control, the cardiovascular disease risks for all participants may have been reduced at a comparable rate.
Source: NEJM; June 24, 2013.