Methodology of a multispecialty outpatient Obesity Treatment Research Program

Despite the large number of U.S. adults who overweight or obese, few providers have ready access to comprehensive lifestyle interventions, the cornerstone of medical obesity management. Our goal was to establish a research infrastructure embedded in a comprehensive lifestyle intervention treatment for obesity. The Obesity Treatment Research Program (OTRP) is a multi-specialty project at Mayo Clinic in Rochester, Minnesota designed to provide a high intensity, year-long, comprehensive lifestyle obesity treatment. The program includes a nutritional intervention designed to reduce energy intake, a physical activity program and a cognitive behavioral approach to increase the likelihood of long-term adherence. The behavioral intervention template incorporated the Diabetes Prevention Program and the Look AHEAD trial materials. The OTRP is consistent with national recommendations for the management of overweight and obesity in adults, but with embedded features designed to identify patient characteristics that might help predict outcomes, assure long-term follow up and support various research initiatives. Our goal was to develop approaches to understand whether there are patient characteristics that predict treatment outcomes.

Does rimonabant independently affect free fatty acid and glucose metabolism?

CONTEXT

Endocannabinoid receptor 1 blockade is proposed to improve metabolic complications of obesity via central and peripheral effects.

OBJECTIVE

Our objective was to test whether rimonabant improves insulin regulation of free fatty acid and glucose metabolism after controlling for fat loss.

DESIGN

This was a double-blind, placebo-controlled substudy of the visceral fat reduction assessed by computed tomography scan on rimonabant (VICTORIA) trial.

PARTICIPANTS AND SETTING

Sixty-seven abdominally obese, metabolic syndrome volunteers age 35-70 yr participated at academic medical center general clinical research centers.

INTERVENTION

Intervention included a 12-month lifestyle weight management program plus rimonabant 20 mg/d or placebo.

MAIN OUTCOME MEASURES

Body composition and two-step euglycemic, hyperinsulinemic clamp before and after intervention were performed. Insulin sensitivity was assessed as insulin concentration needed to suppress by 50% palmitate concentration [IC50(palmitate)], flux [IC50(palmitate)f], and hepatic glucose output [IC50(HGO)] and as insulin-stimulated glucose disposal (Δ glucose disappearance per Δ insulin concentration--glucose slope).

RESULTS

Body fat decreased by 4.5±2.9% (SD) in the rimonabant and 1.9±4.5% in the placebo group (P<0.005). The primary [improvement in IC50(palmitate) and IC50(palmitate)f] and secondary [improvement in IC50(HGO) and glucose slope] outcomes were not significantly different between the rimonabant and placebo groups. Post hoc analyses revealed that 1) changes in body mass index (BMI) and IC50(palmitate) were correlated (P=0.005) in the rimonabant group; this relationship was not significantly different from placebo when controlling for greater BMI loss (P=0.5); 2) insulin-regulated glucose disposal improved in both groups (P=0.002) and correlated with changes in BMI.

CONCLUSIONS

Improvements observed in insulin regulation of free fatty acid and glucose metabolism with rimonabant treatment in humans was not greater than that predicted by weight loss alone.