Major Finding: After 1 year of participation in an intensive lifestyle intervention program, patients with class III obesity lost a mean of 11 kg, compared with 9 kg and 6 kg in patients with class II and class I obesity, respectively.
Data Source: An analysis of 2,503 patients in the multicenter, randomized Look AHEAD clinical trial.
Disclosures: The study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases. Dr. Unick said she had no conflicts of interest.
SAN DIEGO — Obese patients with a body mass index of 40 kg/m
The findings suggest that behavioral weight-loss programs are a viable treatment option for class III obese patients, Jessica L. Unick, Ph.D., said at the meeting.
“Severe obesity is the fastest-growing segment of the overweight population, increasing at a rate of two to three times faster than obesity alone,” said Dr. Unick of the centers for behavioral and preventive medicine at Miriam Hospital, Brown University, Providence, R.I. “Given these alarming statistics as well as the known health consequences associated with this magnitude of obesity, it's critical that we begin to identify successful treatment options for this population.”
She pointed out that currently, behavioral weight-loss programs are typically recommended for individuals with a BMI of less than 40. As a result, “severely obese individuals are often excluded from clinical weight-loss trials, usually due to other obesity-related comorbidities or upper BMI cutoff inclusionary criteria for the study. Therefore, we have limited data regarding the effectiveness of behavioral weight loss programs in this population.”
For the study, Dr. Unick and her associates examined whether severely obese patients randomized to the intensive lifestyle intervention arm of the Look AHEAD trial achieved similar weight losses, experienced comparable changes in cardiovascular disease risk factors, and had been equally adherent to program recommendations at 1 year of treatment, compared with those who had lesser degrees of obesity. The Look AHEAD trial is an ongoing, multicenter, randomized clinical trial examining the long-term effects of an intensive lifestyle intervention program on cardiovascular morbidity and mortality in 5,145 overweight or obese patients with type 2 diabetes from 16 centers in the United States. The individuals will be followed for up to 13.5 years.
To be eligible for the Look AHEAD trial, patients had to have type 2 diabetes, be 45-76 years of age, have a BMI of at least 25 (or at least 27 if taking insulin), have a hemoglobin A1c level of 11% or lower, and meet certain cardiovascular disease cutoff values, including triglycerides below 600 mg/dL and a blood pressure of less than 160/100 mm Hg. The patients were randomized to an intensive lifestyle intervention or to diabetes support and education. The study conducted by Dr. Unick and her associates evaluated only the 2,503 patients randomized to the intensive lifestyle intervention.
The researchers grouped the study participants into one of four categories based on BMI: overweight (25-29), class I obese (30-34), class II obese (35-39), and class III obese (40 or greater). Their mean age at baseline was 59 years.
For the first 6 months of the study, participants attended three weekly group meetings and one individual meeting per month. This was reduced to two group meetings and one individual meeting per month during months 7-12.
Patients in the intensive lifestyle intervention arm were asked to reduce their dietary intake to 1,200-1,800 calories per day. They were provided meal replacements in the form of two meals and one snack per day to help facilitate that goal. They were also asked to progressively increase their level of physical exercise to 175 minutes per week.
“In addition, the participants were given an initial weight loss goal of 10% of initial body weight, and there was a strong behavioral component to this intensive lifestyle intervention,” Dr. Unick said.
She reported that at 1 year, class III obese patients lost a mean of 11 kg, which was significantly greater than the weight loss experienced by the other groups (a mean of 9 kg in the class II obese group, 8 kg in the class I obese group, and 6 kg in the overweight group).
On average, class III obese patients lost 9% of their baseline weight, and 39% lost 10% or more of their baseline body weight. These reductions in weight were significantly greater than those experienced by the overweight group and were comparable to those achieved by patients in the class I and class II groups.
All weight groups had similar improvements in cardiovascular disease risk factors, with the exception of HDL cholesterol level. The class III group had less of an improvement in HDL cholesterol from baseline to 1 year, compared with the other BMI groups.