San Diego, CA—Four-year results of the large, federally funded Look AHEAD trial show that intensive lifestyle intervention (ILI) is superior to usual care (diabetes support and education; DSE) in achieving weight loss and improvements in fitness, glycemic control, and some cardiovascular risk factors in individuals with type 2 diabetes. The magnitude of change in the ILI arm for all parameters was more robust at year 1 and tended to fall off over 4 years, sometimes referred to as “adherence fatigue.” Nevertheless, the 4-year results show that ILI achieved improvement in risk factors and glucose control compared with usual care.
“ILI achieved clinically significant weight loss in all subsets of patients. Nearly 50% of ILI participants maintained a greater than 5% weight loss from baseline at year 4. ILI is more effective in promoting weight loss, fitness, glycemic control, systolic blood pressure control, and HDL-C [high-density lipoprotein cholesterol] levels compared with DSE,” said Xavier Pi-Sunyer, MD, MPH, Director of the New York Obesity Center at St. Luke’s Hospital, New York City, who presented the study design and key results at the 2011 Scientific Sessions of the American Diabetes Association.
Factors that predicted sustained weight loss at year 4 were losing 10% of baseline body weight by year 1, use of meal-replacement products, and increased levels of physical activity. Also, older individuals (aged 65-74 years) had greater weight loss than younger individuals. A somewhat surprising finding of a subanalysis was that severely obese persons gained as much benefit from ILI as the total study population. This group is usually excluded from randomized clinical trials, because of associated morbidities.
The study enrolled 5145 patients with type 2 diabetes, aged 45 to 76 years, who were overweight or obese; one third were minority groups. Patients were randomized to ILI or DSE. ILI focused on weight loss and physical fitness, and depended on group and individual sessions on education and support; the number of monthly sessions was initially 4, and was reduced to 1 face-to-face session and 1 telephone session during years 2 to 4. The goal was 10% weight loss.
At year 4, ILI participants lost a greater percentage of body weight (–6.15% vs –0.88%; P <.001) and had greater improvements in treadmill fitness (12.74% vs 1.96%; P <.001), hemoglobin A1c, systolic blood pressure (P <.0001), and levels of HDL-C, but no difference between groups was seen for low-density lipoprotein cholesterol levels and triglyceride levels. Patients randomized to ILI were significantly more likely to stop insulin therapy (P <.0001) and to stop taking other diabetes drugs compared with the DSE group. Data are not yet available on the effect of ILI versus DSE on cardiovascular end points (primary end point of the trial); planned follow-up is 13.5 years.
Factors associated with successful weight loss were explored in a subanalysis of the Look AHEAD trial. “The more contact time in sessions, the more adherence to the behaviors we were promoting, the greater the weight loss,” said Donna Ryan, MD, Executive Director of the Pennington Biomedical Research Center, Baton Rouge, LA.
Losing 10% or more of baseline body weight accounted for 22% of adherence to ILI; if a person lost 10% or more at year 1, there was a 9.8% odds ratio of losing 10% at year 4, Dr Ryan said.
Intensive Lifestyle Intervention Costs Far Exceed Those of Standard Support, Education
A cost analysis of the Look AHEAD trial presented by Ping Zhang, PhD, Centers for Disease Control and Prevention, Atlanta, GA, showed that intensive lifestyle intervention (ILI) was exponentially more costly than diabetes support and education (DSE). Costs per patient for ILI were:
- Year 1, $3175
- Year 2, $1760
- Year 3, $1214
- Year 4, $1176.
Costs per patient per year for DSE were:
- Year 1, $83
- Year 2, $64
- Year 3, $65
- Year 4, $72.
Dr Zhang said that the ILI in Look AHEAD was about 3 times higher in cost than the ILI in the large Diabetes Prevention Program sponsored by the National Institutes of Health.
“Look AHEAD is the first study to collect costs of an intensive lifestyle intervention for management of type 2 diabetes,” he stated. “The costs can be high in the first year, but are substantially reduced in the following years.”