The Look AHEAD Research Group. Long term effects of a lifestyle intervention on weight and cardiovascular risk factors in individuals with type 2 diabetes: four year results of the Look AHEAD Trial. Arch Intern Med. 2010; 170(17):1566-1575.
Design & Participants
In this multicenter randomized clinical trial, researchers compared the effects of intensive lifestyle intervention (ILI/intervention group) and diabetes support and education (DSE/control group) on the incidence of major cardiovascular disease (CVD) events. The study consisted of 5,145 individuals with type 2 diabetes, recruited at 16 centers in the United States. The participants were 45-76 years of age with a body mass index (BMI) of ³ 25 (³27 in patients on insulin), HbA1c <11%, systolic blood pressure (SBP) <160 mmHg, diastolic blood pressure (DBP) < 100 mmHg and triglycerides <600 mg/dl. The participants were randomized into the ILI/intervention group (2,570 adults) and the DSE/control group (2,575 adults). Both frequency of visits and lifestyle modifications differed in the intervention group compared to the control group. The ILI participants were put on a 1,200-1,800 kcal/day meal plan based on baseline weight and were asked to participate in 175 minutes of physical activity per week. Education on behavioral strategies such as self-monitoring, goal setting, and problem solving were highlighted. The intervention group was seen weekly for the first 6 months and 3 times per month for the remainder of the year. After the 1st year participants were seen individually once per month and, in addition to the 1 visit, were offered a Look AHEAD-approved group class. At each visit, participants were weighed, a new lesson was presented, and self-monitoring records were reviewed. In comparison, the DSE control group had 3 group sessions focused on diet, physical activity, or social support per year for 4.0 to 6.5 years after study randomization, in addition to regularly scheduled clinic visits for annual assessments. They were not educated on behavioral strategies and were not weighed at each session.
The results of the trial were significant: Averaged over the 4 years, participants in ILI experienced significantly greater improvements in weight, fitness, glycemic control, blood pressure, HDL-C and triglycerides than those in DSE. Weight loss was significantly greater in ILI participants compared to DSE each year, and participants in ILI maintained a statistically significant mean weight loss compared to DSE after 4 years (P<.0001). Interesting to note, the ILI participants had a lower use of diabetes drugs and a smaller percentage of ILI participants were put on drugs compared to the DSE group. The only cardiovascular risk factor showing greater improvement (before adjustments) in the DSE group vs. ILI group was LDL-C, and this was because of the increased use of statins in the DSE participants.
It is not surprising that the intervention group was able to adhere to the lifestyle changes and had a greater reduction in CVD risk factors compared to the control group. The intervention group had a total of 72 visits for the first 12 months of treatment. The following items were highlighted in the ILI group: knowledge of diabetes management, caloric control, nutrition and activity; motivation through self efficacy, outcome expectations, and lifestyle modification education; self regulatory skills through social support, goal setting, cognitive restructuring, and relapse prevention; the experience of group and individual counseling; and practical assistance in overcoming environmental barriers. The control group received usual care consisting of 3 group educational/support sessions per year.
Patients can feel overwhelmed when diagnosed with diabetes, often due to the expectation of lifestyle change with minimal clinical support.
Patients can feel overwhelmed when diagnosed with diabetes, often due to the expectation of lifestyle change with minimal clinical support. Exercise and healthy, balanced meals are interventions commonly used by integrative practitioners for diabetic patients. While this trial does a great job of highlighting the importance of these interventions, more significantly it emphasizes the importance of consistent education, support, and behavioral strategies. Although the endpoint of cardiovascular events cannot be determined without further follow-up, it would seem reasonable that the changes noted thus far in the intervention group will result in decreased cardiovascular events based on the reduction of CVD risk factors.
Although this is an impressive trial, it did have some minor limitations. One of the limitations for this trial is that the participants followed up for regular checkups with their usual healthcare practitioner. These practitioners decided when to put the patient on medication and when to decrease or increase medication. Although guidelines for standard of care are the same, slight differences can still occur. This variation could result in mottled outcome of medication use in participants. Another limitation worthy of noting is the lack of clarification around the randomization of the participants. The study mentioned that each clinical center coordinated the randomization of the participants into 1 of the 2 arms of the study; it would be interesting to know the specific parameters used to determine the randomization process within each center.