From Willpower to WillPOWER! Comparative Effectiveness Trials of Weight-Loss Interventions from the POWER Consortium

Published - Written by John Staples

It happens every year. After some champagne, confetti, and a couple choruses of Auld Lang Syne, a great number of us wake up on New Year’s Day resolving to lose weight. A spirit of focused enthusiasm sets in, and doctors, dieticians, and personal trainers are consulted for their advice. Weight-loss products fly off the shelf. Gym membership soars. And then? Often, disappointment sets in. The dual challenges of effective weight loss and sustained behavior change are intimidating even to those with tremendous willpower. If New Year’s resolutions don’t work, what does?

This week, NEJM published reports on two trials that study the comparative effectiveness of weight-loss interventions in patients with obesity and risk factors for cardiovascular disease. Both trials were completed by members of the Practice-based Opportunities for Weight Reduction (POWER) Trials Collaborative Research Group, and were funded at least in part by the National Heart, Lung, and Blood Institute; one trial was also funded in part by Healthways, Inc, a disease management company. Both used weight loss at two years as their primary outcome.

In the first trial, Dr. Thomas Wadden (University of Pennsylvania, Philadelphia, PA) and colleagues randomized 390 obese adult volunteers to one of three groups: usual care, consisting of quarterly primary care practitioner visits; brief lifestyle counseling, consisting of usual care plus monthly individual sessions with a lifestyle coach; or enhanced brief lifestyle counseling, which combined usual care and monthly individual lifestyle coaching sessions with the prescription of sibutramine, orlistat, or meal replacements (according to patient and primary care provider preference). At 2 years, a pre-specified analysis adjusting for baseline differences demonstrated patients in the enhanced brief lifestyle counseling group had significantly greater mean weight loss (4.6kg) than those in the usual care (1.7kg) or brief lifestyle counseling (2.0kg) groups. The difference persisted when individuals receiving sibutramine (now withdrawn from the market due to unacceptable adverse cardiovascular effects) were excluded from the analysis.

Dr. Lawrence Appel (Johns Hopkins University, Baltimore, MD) and colleagues also conducted a comparative effectiveness trial in patients with obesity and at least one cardiovascular risk factor. In this trial,  415 participants were randomized to one of three weight-loss interventions: a self-directed control, in which written information and a single in-person coaching session was provided; a call-center-directed intervention, consisting of weekly engagement with the study’s weight management web site and frequent coaching by telephone; or, an in-person-directed intervention, consisting of weekly engagement with the study’s weight management web site and frequent individual and group in-person coaching sessions. At 2 years, the mean weight loss of the call-center-directed group was 4.5kg, significantly better than that of the self-directed control group (0.8kg), and not significantly worse than that of the in-person-directed intervention group (5.1kg).

The evidence that effective weight loss interventions can be deployed in primary care settings is welcome news, according to an accompanying editorial by Dr. Susan Yanovski (National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD). But Dr. Yanovski also highlights several important unanswered questions: What will happen when patients are asked to bear the costs of these interventions? Do these interventions result in changes to cardiovascular outcomes? How cost-effective are these interventions?

“Practical, scalable, affordable, and effective interventions to achieve sustainable weight loss in the primary care setting are badly needed,” says cardiologist and NEJM executive editor Dr. Gregory Curfman, “These trials provide evidence that may inform the design of weight-loss interventions in future.” The medical community has yet to discover the perfect weight-loss solution.  When we do, though, it will be cause for celebration – maybe even with confetti and low-calorie champagne.