The principal finding of this study was that PCPs, collaborating with medical assistants, helped one group of their obese patients lose an average of 4.7% of their initial weight at 24 months. This loss, which was accompanied by improvements in cardiovascular risk factors, was achieved with enhanced brief lifestyle counseling, which combined quarterly PCP visits, brief lifestyle coaching delivered monthly, and the use of meal replacements or weight-loss medication. Thirty-five percent of the participants assigned to this intervention lost 5% or more of their initial weight, which is a common criterion for clinically meaningful weight loss.11,29
Long-term weight loss in the group that received enhanced lifestyle counseling (as well as in the group that received brief lifestyle counseling without enhancement) was greater than weight loss observed in other primary care trials,5–7,30,31
with the exception of a study involving extremely obese patients who were treated with intensive group lifestyle modification and weight-loss medications.32
Enhanced lifestyle counseling offers a model for treating obesity in primary care practices with the help of regular staff members (PCPs and medical assistants).
As compared with usual care, only the enhanced counseling led to a significant increase in weight loss at month 24; brief counseling without enhancement did not result in the 4-kg weight loss expected in light of the results of the pilot study.9
Participants who received the brief lifestyle counseling attended significantly fewer coaching sessions than did those who received the enhanced counseling, despite the fact that the same personnel delivered both interventions. In contrast, participants who received the usual care lost more than the expected 1 kg, probably because the weight-management support they were given (quarterly PCP visits, a calorie book, and a pedometer) to encourage them to remain in the study was greater than the support that would typically be provided in the primary care setting. Our findings suggest that PCPs may be able to assist one fifth of their obese patients in losing 5% or more of body weight by providing educational materials and briefly discussing weight management at quarterly visits.
Our study shows that combining quarterly PCP visits with brief monthly lifestyle coaching provided by medical assistants does not significantly increase weight loss, as compared with PCP visits alone. The use of specialized personnel (e.g., registered dietitians),15
as well as more intensive coaching (i.e., more than one session per month for the first 3 months), as recommended by the U.S. Preventive Services Task Force,1
could increase weight loss.33
However, both options would have considerable financial and logistic consequences for primary care practices, and as suggested by our attendance data, participants might not be willing to make additional office visits.
The strengths of this study include the randomized design, the provision of interventions by primary care personnel who treated obese patients in their local practices (rather than the provision of interventions by specialized personnel to highly selected volunteer subjects), and the high rate of study completion by participants (86%). Limitations included the provision of free treatment enhancements (which may limit the generalizability of the results); the need for longer follow-up; and the withdrawal of sibutramine from the market, which clouded interpretation of the findings for the group of participants who received enhanced brief lifestyle counseling. Nonetheless, the beneficial effects of this latter approach remained even after analyses were limited to persons who received only meal replacements or orlistat, each of which continues to be available. The study also confirmed the problem of weight regain despite ongoing counseling for weight-loss maintenance.34
Our data support the screening by PCPs of all adults for obesity, as well as efforts to help patients understand the health consequences of excess weight and the benefits of modest weight loss; these practices are consistent with prior recommendations.1,11
By providing enhanced lifestyle counseling, as described here, PCPs could help a considerable minority of obese persons achieve clinically meaningful weight loss,11,29
which they might not achieve if they were simply told to reduce their weight on their own. The treatment model used in this study awaits comparison with community-based approaches,24,35
as well as with electronically delivered interventions (including the Internet,36
and telephone counseling33,38
), which could result in equivalent or greater weight loss. Although our study has shown that primary care personnel can provide effective weight-management support, it has not addressed the more challenging question of who will pay for these or related weight-loss interventions.39