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Look AHEAD study

Lifestyle intervention gives 'clinically significant' weight loss

Intervention resulted in a mean loss of 8.6% of initial weight over 12 months
Study looked at over 5,000 patients with T2DM
Interventions included calorie controlled diet and diabetes education

The Look AHEAD (Action for Health in Diabetes) study, recently published online in Obesity 2009, is the first randomised, controlled trial to assess the long-term health consequences of intentional weight loss in overweight and obese individuals with type 2 diabetes. The study provides an analysis of first year weight losses in participants and also identifies factors associated with success.

Lead investigator, Dr Thomas A Wadden, University of Pennsylvania School of Medicine, Pennsylvania, reported that 5,145 participants with type 2 diabetes were randomly assigned to a usual care condition (Diabetes Support and Education – DSE) or to an intensive lifestyle intervention (ILI) group with a goal of inducing a loss of 7% of initial weight and increasing physical activity to 175min/week. Recruitment took place across 16 centres in the US, and all patients (45–74 years of age) had a BMI of 25 or above (or 27or above if taking insulin).

Wadden explained that before randomisation, eligible participants received an initial session of diabetes education that included general recommendations for adopting healthy eating and activity habits, and addressed the management of hypoglycemia and foot care. Participants who remained interested in the study were then randomly assigned with equal probability to the ILI and DSE conditions.

A total of 2,496 (97.1%) ILI and 2,463 (95.7%) DSE participants completed the one-year assessment (p=0.004). The 186 patients who did not complete the assessment were significantly (p<0.001) more likely to be taking insulin than were completers (21.0% vs. 15.1%, respectively). The non-completers included 101 individuals who missed the scheduled assessment and will be contacted for future follow-up visits. An additional 76 participants withdrew from the trial, and nine individuals died during the first year.

Weight loss in ILI and DSE groups

After year one, the results revealed that ILI induced a mean loss of 8.6% of initial weight, compared with 0.7% for the control condition group. It was reported that 55.1% of ILI participants met the study-wide goal of losing 7% of initial weight, compared with only 7% of individuals in DSE, and approximately 45% of DSE participants gained weight during the year, compared with only 7.3% of individuals in ILI (p<0.001). Furthermore, the researchers found that use of insulin and other diabetes medications was associated with smaller weight losses. In the DSE group, weight losses for participants who took insulin, other diabetes medications, or no medications were 0.4%, 0.7%, and 1.0%, respectively (with no significant differences among groups).

Weight loss within the ILI group

Wadden explained that patients assigned to the ILI group (n=2,570) lost an average of 8.2% at week 26, which increased to 8.7% at one year. In terms of demographics in the ILI group, men lost significantly (p<0.001) more weight than women at one year (9.2%  vs. 8.1%). Among men, 58.5% met the study-wide criterion of a 7% weight loss, and 41.6% lost 10%. Comparable values for women were 52.9 and 35.2%, respectively. Interestingly, the study’s oldest participants (65–74 years of age at baseline) lost a significantly (p=0.04) greater percentage of initial weight than those in the middle group (55–64 years) or the youngest group (45–54 years), with one-year losses of 9.4%, 8.5%, and 7.9%, respectively.

Treatment adherence and weight loss

According to the researchers, during the first year patients in the ILI group attended an average of 35.4/42 group and individual exercise sessions. It was observed that the more sessions’ patients were involved in, the more weight they lost at one year. Meal replacements also contributed to significant weight loss, particularly in the first six months. Patients in the higher quartile of meal replacement use had four time greater odds of reaching the 7% weight loss and 4.1 times greater odds of reaching the 10% goal than did patients in the lowest quartile, said the authors.

Orlistat

Orilstat was administered to 291/722 patients who lost <5% of initial weight in the first six months, reported Wadden. Those who took the medication had lost 1.8% at month six, compared with 2.0% for those who did not. One-year weight losses of these two groups were 3.4% and 2.2%, respectively (p<0.02). Of the 780 participants who had lost 5.0–9.9% at month six and were eligible (but not encouraged) to take medication, only 201 chose to. Six-month weight losses of those who elected to use the medication were significantly (p<0.001) smaller than those of participants who declined it (6.9% vs. 7.7%).

The researchers further explained that of the 838 participants who had lost 10% or more in the first six months, 412 were eligible to take the medication from months seven to 12 by virtue of regaining 2% or more of their lost weight. The 31 individuals who chose to use orlistat had a mean loss of 12.6% at month six, compared with 14.1% for those who did not use it (p<0.03). One-year weight losses for the two groups were 9.8% and 14.8%, respectively (p<0.001). The 523 total participants who took orlistat reported doing so for an average of 16.7 weeks from months seven to 12.

“Further analyses showed that participants who were encouraged to take orlistat (i.e., <5% loss) attended significantly fewer treatment sessions during the first six months than those who were eligible (but not expressly encouraged) to take the medication (i.e., <10% loss) who, in turn, attended significantly fewer sessions than individuals who were ineligible to take the drug (i.e., >10% loss),” said Wadden.

Conclusions

The study’s take-home message was that an ILI induced a ‘clinically significant weight loss’ in all groups of patients. “An intensive group lifestyle intervention induced a mean loss of 8.6% of initial weight in overweight and obese patients with type 2 diabetes,” said the authors.

“The intervention was clinically effective in all subsets of an ethnically and demographically diverse population. Greater self-reported physical activity and consumption of meal replacements, as well as more frequent treatment attendance, were associated with greater weight loss. Study efforts are currently devoted to helping participants maintain their lost weight to have the best opportunity to determine whether intentional weight loss reduces cardiovascular mortality and morbidity."

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