Medical Management of Extreme Obesity Effective in the Primary Care Setting

Results from a randomized, controlled, clinical trial [Arch Intern Med. 2010;170(2):146-154] show that primary care practices can initiate effective medical management programs to treat extremely obese patients but maintaining weight loss remains difficult and needs further study.

Although therapeutic techniques that include diet, exercise, and drug and behavioral therapies are commonly used to treat obesity, few data exist on using these techniques to treat extreme obesity, and surgery is often considered the best treatment. However, surgery is often not available and other options are needed to treat the many people with extreme obesity.

The Louisiana Obese Subjects Study was conducted to test the hypothesis that primary care physicians could implement an effective medical management program to treat patients with extreme obesity. Using a pragmatic clinical trial study design, which compares clinically relevant alternative interventions in a diverse study population from heterogeneous practice settings and collects data on a broad range of health outcomes, investigators randomized 390 extremely obese participants from 8 clinics (7 primary care practices and 1 research clinic) to an intensive medical intervention (IMI) (n=200) or usual care condition (UCC) (n=190).

All participants in the study were aged 20 to 60 years, had a body mass index of ≥40, had blood levels (hematocrit, white blood cell count, platelet count) and thyrotropin levels within reference range, and uric acid level <9.0 mg/dL. Participants were excluded from the study if they were pregnant, had a history of major depression, suicidal behavior, eating disorder, hospitalization for mental disorder or substance abuse in the previous year, active cancer, cardiovascular or cerebrovascular disease event in the previous year, heart failure, untreated high blood pressure (≥160/100 mm Hg), or were on current drugs for weight loss.

Participants randomized to IMI were treated with evidence-based approaches based on 3 recommended phases of treatment that included an initial low-calorie (900-kcal) liquid diet for 12 weeks (phase 1), a highly structured diet and medication where recommended along with behavior therapy for 4 months (phase 2), and weight-loss medications and 1 daily meal replacement along with monthly group sessions during months 8 to 24 (phase 3).

Patients randomized to UCC were instructed to use the Mayo Clinic Weight Management Web site, and were given annual visits to their clinics at 1 and 2 years.

Of the 390 participants, 75% were white and 83% were women with a mean age of 47 years. At 2-year follow-up, the retention rates between the IMI and UCC groups were similar (51% and 46%, respectively).

At 2 years, weight loss in the IMI group was significantly greater than in the UCC group. In the IMI group, 31% achieved a ≥5% weight loss and 7% achieved a ≥20% weight loss compared to 9% and 1%, respectively, in the UCC group (P<.001).

To further assess weight loss, the study used baseline observation carried forward (BOCF) analysis (a statistical analysis that looked at baseline observations carried to 2 years) and last observation carried forward (LOCF) analysis (last assessment data carried forward) for missing data.

Based on these analyses, the study found a mean ±SEM weight loss of –4.9% ± 0.8% in IMI versus –0.2% ± 0.3% in UCC for BOCF (P<.001). At year 2, the LOCF for the IMI group was –8.3% ± 0.8% and –0.0% ± 0.4% for the UCC group (P<.001).

Overall, the study found that a total of 101 participants who completed IMI lost –9.7% ± 1.3% (–12.7 ± 1.7 kg), whereas 89 participants who completed UCC lost –0.4% ± 0.7% (–0.5 ± 0.9 kg) (P<.001).

Although the investigators do not propose that IMI replace bariatric surgery, they do suggest, based on these results, that physicians should not be pessimistic about helping extremely obese patients who do not have access to bariatric surgery lose weight.

The results “indicate that physicians with a modicum of training can deliver an intervention with benefit for about a third of those they see,” said the authors.

Among the several caveats to the study, including the use of a treatment paradigm that did not always mimic medical practices, the study also highlighted the difficulty of retention that the investigators say probably mimics real-world weight-loss behavior.—Mary Beth Nierengarten