Rapid glycemic improvements following Roux-en-Y gastric bypass (RYGB) are frequently attributed to the enhanced GLP-1 response, but causality remains unclear. To determine the role of GLP-1 in improved glucose tolerance after surgery, we compared glucose and hormonal responses to a liquid meal test in 20 obese participants with type 2 diabetes mellitus who underwent RYGB or nonsurgical intensive lifestyle modification (ILM) (n = 10 per group) before and after equivalent short-term weight reduction. The GLP-1 receptor antagonist exendin(9–39)-amide (Ex-9) was administered, in random order and in double-blinded fashion, with saline during two separate visits after equivalent weight loss. Despite the markedly exaggerated GLP-1 response after RYGB, changes in postprandial glucose and insulin responses did not significantly differ between groups, and glucagon secretion was paradoxically augmented after RYGB. Hepatic insulin sensitivity also increased significantly after RYGB. With Ex-9, glucose tolerance deteriorated similarly from the saline condition in both groups, but postprandial insulin release was markedly attenuated after RYGB compared with ILM. GLP-1 exerts important insulinotropic effects after RYGB and ILM, but the enhanced incretin response plays a limited role in improved glycemia shortly after surgery. Instead, enhanced hepatic metabolism, independent of GLP-1 receptor activation, may be more important for early postsurgical glycemic improvements.
This narrative review examines randomized controlled trials of the management of obesity in primary care practice, in light of the Centers for Medicare and Medicaid Services’ decision to support intensive behavioral weight loss counseling provided by physicians and related health professionals. Mean weight losses of 0.1–2.3 kg were observed with brief (10- to 15-min) behavioral counseling delivered by primary care providers (PCPs) at monthly to quarterly visits. Losses increased to 1.7–7.5 kg when brief PCP counseling was combined with weight loss medication. Collaborative treatment, in which medical assistants delivered brief monthly behavioral counseling in conjunction with PCPs, produced losses of 1.6–4.6 kg in periods up to two years. Remotely delivered, intensive (>monthly contact) behavioral counseling, as offered by telephone, yielded losses of 0.4–5.1 kg over the same period. Further study is needed of the frequency and duration of visits required to produce clinically meaningful weight loss (>5%) in primary care patients. In addition, trials are needed that examine the cost-effectiveness of PCP-delivered counseling, compared with that potentially provided by registered dietitians or well-studied commercial programs.
Primary care practitioners (PCPs) have been encouraged to screen all adults for obesity and to offer behavioral weight loss counseling to affected individuals. However, there is limited research and guidance on how to provide such intervention in primary care settings. This led the National Heart, Lung, and Blood Institute (NHLBI) in 2005 to issue a request for applications to investigate the management of obesity in routine clinical care. Three institutions were funded under a cooperative agreement to undertake the Practice-based Opportunities for Weight Reduction (POWER) trials. The present article reviews selected randomized controlled trials, published prior to the initiation of POWER, and then provides a detailed overview of the rationale, methods, and results of the POWER trial conducted at the University of Pennsylvania (POWER-UP). POWER-UP’s findings are briefly compared with those from the two other POWER Trials, conducted at Johns Hopkins University and Harvard University/Washington University. The methods of delivering behavioral weight loss counseling differed markedly across the three trials, as captured by an algorithm presented in the article. Delivery methods ranged from having medical assistants and PCPs from the practices provide counseling to using a commercially-available call center, coordinated with an interactive web-site. Evaluation of the efficacy of primary care-based weight loss interventions must be considered in light of costs, as discussed in relation to the recent treatment model proposed by the Centers for Medicare and Medicaid Services.
Objective: Obesity and depression frequently co-occur, and each increases risk for cardiovascular disease (CVD). This study tested whether a combined treatment, targeting obesity and depression simultaneously, would yield greater improvements in weight, mood, and CVD risk factors than treatments that targeted each disease individually. Methods: Seventy-six participants with obesity and major depression were randomly assigned to (1) behavioral weight control (BWC), (2) cognitive behavioral therapy for depression (CBT-D), or (3) BWC combined with CBT-D. Participants were provided 18 group treatment sessions over 20 weeks. Mood, weight, and CVD risk were assessed at baseline and weeks 8 and 20, with a follow-up visit at week 46. Results: At week 20, participants in combined treatment lost significantly (P < 0.02) more weight (5.2% 6 1.2%) than those assigned to CBT-D (0.8% 6 1.3%) and comparable amounts as those in BWC (3.5% 6 1.3%). Depression scores decreased significantly from baseline levels in each group, with no significant differences between groups. All three groups showed significant improvements in 10-year CVD risk, with no significant differences between groups. Groups did not differ significantly on any of these measures at week 46. Conclusions: BWC yielded short-term improvements in weight, mood, and CVD risk, comparable to a combined treatment that incorporated CBT-D. Results require replication with a larger sample size.
ObjectiveTo determine the effects of weight loss and weight loss maintenance (WLM) on weight-specific health-related quality of life (HRQOL) in a 66-week trial.MethodsAdults with obesity (N=137, 86.1% female, 68.6% black, mean age=46.1 years) who had lost ≥5% of initial weight in a 14-week intensive lifestyle intervention/low-calorie diet (LCD) program were randomized to lorcaserin or placebo for an additional 52-week WLM program. The Impact of Weight on Quality of Life (IWQOL-Lite) scale (including five subscales), Patient Health Questionnaire-9 (depression), and Perceived Stress Scale were administered at the start of the 14-week LCD program, randomization, and week 52 of the randomized controlled trial (RCT; i.e., 66 weeks total).ResultsSignificant improvements in all outcomes, except weight-related public distress, were found following the 14-week LCD program (ps<0.05). Improvements were largely maintained during the 52-week RCT, despite weight regain of 2.0–2.5kg across treatment groups. Participants who lost ≥10% of initial weight achieved greater improvements in physical function, self-esteem, sexual life, and the IWQOL-Lite total score than those who lost <5%, and did not differ from those who lost 5–9.9%.ConclusionsImprovements in weight-specific HRQOL were achieved with moderate weight loss and sustained during WLM.
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