Objectives

The POWER-UP trial tested the effectiveness of three primary care practice behavioral interventions in reducing weight. The primary aim of the study was to show that both brief and enhanced brief lifestyle counseling would result in significantly greater weight loss at 24 months than would usual care.

Background

Investigators are searching for new approaches to the treatment of obesity during routine medical visits. Trials in which primary care providers (PCPs) offer counseling about diet and activity have led to weight loss of 2.5 kg or less over study periods ranging from 6 to 18 months. Limited treatment contact is probably responsible for this modest degree of weight loss. Given the demands on providers' time, an increase in the frequency of PCP counseling does not appear to be feasible. As an alternative, Tsai et al. trained medical assistants to deliver individual lifestyle counseling with the use of an abbreviated version of the Diabetes Prevention Program. Overweight patients who received eight brief counseling sessions (and met quarterly with their PCP to manage coexisting illnesses) lost 4.4 kg in 6 months, as compared with 0.9 kg for the patients in the control group, who were limited to quarterly PCP visits. The POWER-UP study expanded on this pilot investigation by assessing brief lifestyle counseling delivered monthly in a 2-year, randomized trial conducted in the primary care setting.

Participants

390 participants were recruited and treated at six primary care practices owned by Penn Medicine. Eligibility criteria included an age of 21 years or older, a body-mass index of 30 to 50, and at least two of five components of the metabolic syndrome to increase the likelihood that the participants would have cardiovascular risk factors.

Design

All participants were prescribed the same goals with respect to diet and physical activity but were provided with different levels of support to achieve them. Participants whose weight was less than 113.4 kg were prescribed a balanced diet of 1200 to 1500 kcal per day (1500 to 1800 kcal per day for participants who weighed 113.4 kg or more), which consisted of approximately 15 to 20% kcal from protein, 20 to 35% kcal from fat, and the remainder from carbohydrate. All participants were instructed to gradually increase their physical activity to 180 minutes per week and were given a pedometer, a calorie-counting book, and handouts from Aim for a Healthy Weight. Weight was measured at baseline and at 6, 12, 18, and 24 months. Waist circumference, blood pressure, and fasting levels of blood glucose, triglycerides, and cholesterol were assessed at baseline and at months 6, 12, and 24.

Participants assigned to usual care were scheduled for quarterly PCP visits during the 24 months of the study to address coexisting illnesses. At each visit, the PCP spent approximately 5 to 7 minutes reviewing the participant's weight change and discussing the information provided in the handouts. The PCPs were instructed not to provide specific behavioral strategies for changing eating and activity habits.

Participants assigned to brief lifestyle counseling were scheduled for the same quarterly PCP visits as the usual-care group but also spent 10 to 15 minutes each month with an auxiliary health care provider (medical assistant), referred to as a lifestyle coach, who delivered treatment by following abbreviated lessons from the Diabetes Prevention Program.

Participants assigned to enhanced lifestyle counseling had the same PCP and counseling visits as those assigned to brief lifestyle counseling. However, in consultation with their PCP, they also chose to take sibutramine, orlistat, or meal replacements to increase weight loss, beginning 1 month after treatment began. Participants were allowed only one enhancement at a time, but could switch between them with the approval of their PCP. After sibutramine was removed from the market, participants who took this medication switched to either meal replacements or orlistat.

Conclusions

Weight loss at 24 months with usual care, brief lifestyle counseling, and enhanced brief lifestyle counseling was 1.7±0.7, 2.9±0.7, and 4.6±0.7 kg, respectively. Initial weight decreased at least 5% in 21.5%, 26.0%, and 34.9% of the participants in the three groups, respectively. Enhanced lifestyle counseling was superior to usual care on both these measures of success with no other significant differences among the groups.

N Engl J Med. 2011 Nov 24;365(21):1969-79.

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