Tuesday, 23 June 2015

SPHPM researchers win grant for multifaceted obesity research study

SPHPM researcher Associate Professor Wendy Brown was recently awarded a significant grant from the Apollo Endosurgery Inc (Apollo) for research she is leading on obesity, as a part of the CORE Research Plan 2015.

Professor Brown is the Director of SPHPM’s Centre for Obesity and Research Education (CORE
). The grant totals US $130,000 for this multi-project study that focus on the long term health changes following weight loss surgery.  The studies include a five-year follow up of diabetic patients who have undergone weight loss surgery, a five-year follow-up of patients with the metabolic syndrome who have undergone weight loss surgery as well as long term follow up of patients who were overweight with diabetes who underwent bariatric surgery as a part of a randomised controlled trial.

“The World Health Organisation estimates that 44 per cent of cases of diabetes are contributed to or caused by obesity.  Weight loss has been shown to be one of the most effective ways of controlling diabetes,” Professor Brown said. 

CORE has been involved in two randomised controlled trials in diabetic patients comparing the efficacy of weight loss surgery to traditional diet and exercise programs.  Both trials showed that the majority of patients required no other treatment other than surgery at two years. 

However, Diabetes is a chronic condition requiring lifelong care and there is very little known about the impact of bariatric surgery on diabetes in the longer term, nor if it changes the complications of diabetes. 

“In the short term, we have shown weight loss surgery to be highly cost effective, however, we do not yet know if this is a sustained effect,” Professor Brown said. 

There are two studies planned to address this important long term question.  The researchers will firstly follow up 609 patients they have been prospectively tracking in their database who were diabetic at baseline and have had bariatric surgery more than five years ago. They will measure change in diabetes treatments as well as other diseases associated with diabetes, and calculate the cost effectiveness of weight loss surgery as diabetic care.  In addition, they will follow up patients who were recruited for the weight loss surgery in overweight diabetics’ trial, as this cohort is now also beyond five years, using the same measures.

The metabolic syndrome consists of a cluster of risk factors that predict progression to type 2 diabetes and heart disease. There are differing definitions of the metabolic syndrome, however, the central feature of these definitions is insulin resistance, which is a common complication of obesity. While we do not know how obesity causes metabolic syndrome, abnormalities of hormones derived from the small bowel (gut hormones) or fat tissue (adipokines) have been implicated. Whilst these gut hormones and/or adipokines may be targeted in the future, weight loss is currently the recommended treatment for metabolic syndrome.

“We know from two randomised controlled trials, with support from multiple observational studies, that substantial weight loss following laparoscopic adjustable gastric banding (LAGB) is associated with resolution of the metabolic syndrome.

“In the initial study where the principal entry criterion was mild to moderate obesity (BMI 30-35), 38 per cent of both groups of study participants had the metabolic syndrome at commencement. At completion there was a non-significant reduction to 24 per cent in the non-surgical group and a highly significant reduction to 3 per cent in the surgical group,” Professor Brown said.

These findings were confirmed in a study of surgical weight loss versus optimal medical management in patients with type 2 diabetes. The metabolic syndrome was present, according to the ATP III criteria, in 98 per cent of both groups initially. At the completion of two years of study, the surgical group had lost 63 per cent of their excess weight and the metabolic syndrome was reduced by 70 per cent, a highly significant difference from the non-surgical group who lost only 4 per cent of their excess weight and had the incidence of the metabolic syndrome reduced by 14 per cent.

“These studies demonstrated a clear relationship between weight loss and the resolution of the metabolic syndrome. However, the exact relationship between weight loss and resolution of metabolic syndrome following LAGB has not been determined. In addition, the roles of gut hormones and adipokines in this process are not known,” Professor Brown said.

Two key questions remain:
1. How critical is the amount of weight loss for resolution of the metabolic syndrome?
2. Is resolution of metabolic syndrome associated with changes in specific gut hormones and/or adipokines?

The current study has followed a cohort of 108 patients with metabolic syndrome who underwent weight loss surgery with regular blood tests and measurements of waist and weight for two years. The aim was to identify at which point on the weight loss curve maximum health benefit was gained.  The current project will follow these same patients up at five years to see if any health benefit is sustained. 
CORE is dedicated to understanding and optimally managing the chronic disease of obesity and measuring the effects of weight loss on health, quality of life and survival. Researchers at CORE are working to identify optimal methods for the safe, cost-effective, long-term management of this disease, as well as implementing strategies in the community for overall improved public health outcomes.
CORE takes a multidisciplinary approach to the study of obesity, integrating a clinical obesity management program with strengths in medicine, surgery, psychology, epidemiology, public health, and professional and community education.

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