Results of this review reveal how little research has been conducted on the management of obesity in primary care practice. Of the ten studies that met criteria for inclusion, only two met the Task Force’s recommendation of providing a high-intensity intervention (at least two visits per month for the first 3 months).26,27
One of these two studies incorporated collaborative obesity treatment in which a dietitian met with patients twice a month and provided meal replacements.26
Participants lost 7.7 kg, which met the criterion of clinically significant weight loss (i.e., ≥5% of initial weight). The other high-intensity trial, which provided twice monthly contact by phone for the first 3 months, produced a loss of 4.3 kg.27
Weight loss, however, in this latter study was calculated from a completers analysis (based on 50% of participants) and is likely to overestimate the efficacy of the intervention. Of the remaining eight trials, four were of moderate intensity (at least one counseling visit per month), and four were of low intensity (<1 visit per month). Two of the four low-intensity studies produced a clinically significant weight loss by combining lifestyle counseling with either sibutramine or orlistat.33,35
Of the three studies that combined counseling and pharmacotherapy, two trials sought explicitly to simulate brief primary care office visits but were conducted in research clinics.29,35
Thus, the results of these studies must be interpreted with caution.
None of the four studies in which PCPs provided low- to moderate-intensity behavioral counseling alone30–32,34
resulted in clinically significant weight loss. Weight losses in the active treatment arms of these trials ranged from 0.1 kg to 2.3 kg. The Task Force gave low- and moderate-intensity behavioral counseling an “I” recommendation (insufficient evidence for or against). The results of this review suggest that low- and moderate-intensity counseling, delivered by a PCP alone, is unlikely to result in clinically significant weight loss.
As noted previously, all but one of the ten trials reviewed here were conducted prior to the Task Force’s recommendation for high-intensity counseling. This recommendation was based largely on the results of efficacy trials, such as the Diabetes Prevention Program, that were conducted in academic medical centers. The time, effort, and expense required for PCPs to provide such care would appear to be prohibitive for most practitioners in the absence of adequate reimbursement and with the already pressing demands of office practice.36–38
However, further research clearly is warranted to assess the results of PCPs’ providing high-intensity behavioral counseling, as recommended by the Task Force. Studies should include economic analyses to determine the costs and cost-effectiveness of such care as compared to self-help (e.g., Take off Pounds Sensibly) and commercial (e.g., Weight Watchers) programs.
The selection criteria for this review were not designed to capture studies in which the PCP may elect to play a more supportive or consultative role (e.g., assess, agree, advise, assist, arrange) and refer patients to more intensive weight loss interventions that are delivered outside of primary care settings. These treatment options have been summarized in detail in previous reviews.21,39–44
Commercial programs, such as Weight Watchers and Jenny Craig, have been shown to produce weight losses of 5 to 7% of initial weight.45,46
Intensive behavioral treatments provided in academic medical centers, such as in the Diabetes Prevention Program,4
can help patients achieve a weight loss of 7–10%.47
Medically supervised programs (OPTIFAST, Health Management Resources) may induce losses of 15–25% of initial weight using meal replacements,48–52
although patients have difficulty sustaining losses of this size, even when provided weight maintenance therapy.48,51,53
Pharmacotherapy (e.g., orlistat, sibutramine), when prescribed alone, produces modest losses of 4 to 5% of initial weight.54
However, interventions that combine pharmacotherapy with intensive lifestyle modification may induce losses of 8–12% of initial weight.35,55–57
Medication must be taken long-term to maintain weight loss.56,58
Bariatric surgery is the most effective method of inducing and maintaining weight loses of 15% (gastric banding) to 25% (gastric bypass).40,42
Surgery has been shown to ameliorate (or fully control) co-morbid conditions, particularly type 2 diabetes,40,59
and in a matched cohort study, to reduce mortality.60
Surgery also carries the highest risks of complications, including peri-operative mortality.61
PCPs who elect not to provide behavioral weight counseling themselves must still play a critical role in assessing and treating obesity-related cardiovascular risk factors. Tight control of type 2 diabetes, hypertension, and hyperlipidemia—all of which are common among overweight and obese individuals—is associated with reductions in morbidity and mortality.62–65
A recent paper underscored the importance of treating CVD risk factors in overweight and obese individuals.66
Once they have evaluated and treated obesity-related risk factors, PCPs can identify the most favorable weight management options for a given patient. In addition to guidance provided by the American Medical Association and the American College of Physicians, the National Heart Lung and Blood Institute devised an algorithm for obesity treatment based on BMI and on the patient’s number of CVD risk factors.5
Options range from a comprehensive program of lifestyle modification (i.e., diet, exercise, and behavior therapy) to bariatric surgery. PCPs who work in integrated health-care systems may have access to this range of weight management interventions.67–71
Those who do not have such access in their practice settings can refer patients to commercial or self-help programs or to weight loss specialists, as described above.
Research on the management of obesity in primary care is in its infancy. Little is known about the clinical and cost-effectiveness of weight management provided by PCPs. Results of this review suggest that: (1) low-intensity PCP counseling alone is insufficient for achieving clinically meaningful weight loss in obese adults, and (2) available data do not indicate how best to incorporate PCPs into more intensive approaches (e.g., collaborative treatment) to achieve this goal. More research is needed on collaborative interventions that involve other members of the clinical care team, as well as call centers and other community linkages.72,73
Without more effective therapies, greater resources in their practices, and more adequate reimbursement,74,75
PCPs alone cannot be expected to provide effective weight management for all of their patients who require it.