Dr. Sharma's Obesity Notes

Regular readers are by now quite familiar with the Edmonton Obesity Staging System (EOSS), which describes how ’sick’ rather than just how ‘big’ patients are.

In a paper just published in OBESITY SURGERY, we discuss how EOSS could be applied to better determine indications for bariatric surgery.

As we point out:

“…health technology assessments specify that bariatric surgery is cost-effective in patients with diabetes (EOSS stage 2). In contrast, the cost-effectiveness of bariatric surgery in patients without comorbidities (EOSS <2) is far less clear. Thus, it is likely that a formal health economics analysis based on the EOSS criteria will support the cost-effectiveness of bariatric surgery for EOSS 2/3 patients, with minimal (if any) cost-effectiveness (even in the long-term) in EOSS 0/1 individuals.”

We also note that:

“It may be argued that bariatric surgery prioritized to EOSS scores 2 and 3, who have increased severity of obesity-related comorbidities, rather than scores 0/1 may miss the opportunity to apply bariatric surgery as a preventative measure. However, in a public-funded health-care system, with limited access and resources, it is prudent to prioritize these resources to those in greatest need. In addition, there is little known about the natural history of obesity, and thus, it remains challenging to predict who will indeed progress to higher EOSS stages and who will remain stable.”

Clearly, our recent publications on EOSS have made it evident that BMI criteria alone are neither a good measure of health nor an adequate predictor of mortality.

Whatever the utility of BMI in population surveys may be, it’s use in clinical decision making is clearly limited - this will need to be reflected in future guidelines and practice recommendations.

AMS
Edmonton, Alberta

Gill RS, Karmali S, & Sharma AM (2011). The Potential Role of the Edmonton Obesity Staging System in Determining Indications for Bariatric Surgery. Obesity surgery PMID: 22002510

Readers may recall previous posts on how the risk of obesity in offspring of mothers, who undergo surgery prior to conception, is dramatically reduced.

That is not what this post is about.

Rather, a study by Woodard and colleagues from Stanford University, just published in the Archives of Surgery, suggests that there may be a positive ‘collateral’ effect on body weight and lifestyle in family members of patients undergoing bariatric surgery.

Thus, an analysis of 35 adult family members (60% of who were obese) and 15 children (73% of who were obese) of 35 patients who underwent Roux-en-Y gastric bypass surgery, showed significant weight loss or less weight gain than expected in the adult family members and kids, respectively.

This weight loss in family members was associated with increased daily physical activity levels, improved eating habits, less emotional eating and reduced alcohol consumption.

Thus, it appears that undergoing bariatric surgery well may have substantial beneficial effects on the health of other family members - both partners and kids.

Although I have heard this anecdotally from some of my patients, I wonder if others have made similar observations in their patients.

I also wonder how such findings would be reflected in health-economic assessments of bariatric surgery.

AMS
Edmonton, Alberta

Woodard GA, Encarnacion B, Peraza J, Hernandez-Boussard T, & Morton J (2011). Halo effect for bariatric surgery: collateral weight loss in patients’ family members. Archives of surgery (Chicago, Ill. : 1960), 146 (10), 1185-90 PMID: 22006878

Early this year, as part of the Alberta-Saxony Obesity Research and Training Alliance (ASORTA), we hosted the first International School on Obesity Research and Management (ISORAM).

This event was attended by over 50 faculty and trainees from Alberta and Germany.

In a follow-up to this immensely successful event, we are now planning ISORAM ‘12, which will be held from March 25-30, 2012, at the Chateau Lake Louise, in Alberta, Canada.

This time the focus will be on all aspects of metabolic and bariatric research as well as medical and surgical management of patients with severe obesity.

The course is open to all health professionals from around the world, who would like to hone their expertise in bariatric medicine and metabolic surgery.

The program, which will offer more than 40 hrs of teaching and interactive workshops, will also include ample time for informal networking and scientific exchange with the international faculty in the unique picturesque surroundings of one of Canada’s premier ski resorts.

Specifically, ISORAM ‘12 has the following objectives:

• To provide participants with a sound understanding of the scientific and methodological issues in bariatric medicine and surgical practices.

• To build participants knowledge in the areas of:

a. Clinical assessment and management of bariatric patients
b. Current best practices in dietary, psychological and behavioural management of bariatric patients
c. Current best practices in patient selection and preparation
d. Current understanding of the biology of metabolic and bariatric surgery patients
e. Interdisciplinary obesity research and practice.

• To educate participants in new developments in:

a. Medical and behavioural management of severe obesity
b. Nutritional and psychosocial complications in bariatric patients
c. Emerging devices in obesity management
d. Rehabilitation issues in bariatric care

• To give participants an understanding of health services/health systems impact on issues related to bariatric care

More information on this event can be here.

Please indicate your interest in learning more about and perhaps participating in this event here.

AMS
Edmonton, Alberta

Yesterday, I discussed the strong interest in trying to understand why exactly bariatric surgery leads to an often dramatic improvement (if not resolution) of type 2 diabetes.

Additional insights into this topic comes from Marzieh Salehi and colleagues in a paper just published in Diabetes.

The paper takes advantage of the fact that some patients undergoing gastric bypass (GB) surgery experience significantly increased insulin secretion following a meal, sometimes even resulting in clinically significant hypoglycaemia.

In order to test the hypothesis that this increase in insulin secretion is in part mediated by the incretin glucagon-like peptide 1 (GLP-1), asymptomatic individuals with previous GB, 10 matched healthy nonoperated control subjects, and 12 patients with recurrent hypoglycemia after GB were examined with and without administration of the GLP-1 receptor antagonist exendin-(9-39).

Blocking GLP-1 significantly reduced postprandial insulin secretion in GB patients than in the non-surgical controls. However, in the hypoglycaemic GB patients, GLP-1 appeared to account for about 45% of increased insulin secretion, not much more than in the non-hypoglycemic surgical subjects.

Glucagon was suppressed similarly by hyperglycemia in all groups but rose significantly after the meal in surgical individuals but remained suppressed in nonsurgical subjects. GLP-1 receptor blockade increased postprandial glucagon in both surgical groups.

As the authors conclude,

“Increased GLP-1-stimulated insulin secretion contributes significantly to hyperinsulinism in GB subjects. However, the exaggerated effect of GLP-1 on postprandial insulin secretion in surgical subjects is not significantly different in those with and without recurrent hypoglycaemia.”

This means that additional factors are probably involved in the hypoglycaemic response seen in some GB patients.

As pointed out in an accompanying editorial by Jens Juul Holst, however, these findings may be more difficult to interpret due to several features of the study design used by Salehi and colleagues. Thus, without going into too many methodological details, there are questions about whether or not the approach used in this study fully explored (or rules out) the role of GLP-1 in the hypoglycaemic response.

Nevertheless, the study certainly supports the notion that increased secretion of GLP-1 following GB surgery, together with other mechanisms including secretion of other enteric hormones, quicker passage of food through the small bowel, reduction in liver fat, and weight loss in general, may all play a role in the substantial glycemic improvements seen with GB surgery in patients with type 2 diabetes.

Thus, while administration of GLP-1 analogues can potentially mimic some of the euglycemic effects of bariatric surfer, it is unlikely that injections of GLP-1 analogues alone will likely result in the same dramatic effects seen with GB surgery.

On the other hand, even if GLP-1 analogues can only deliver some of the potential benefits seen with surgery, I am sure that many patients would likely prefer forgoing some of the benefits in favour of a simple daily injection.

AMS
Edmonton, Alberta

Hat tip to Richard Lehner for alerting me to these articles.

Salehi M, Prigeon RL, & D’Alessio DA (2011). Gastric bypass surgery enhances glucagon-like Peptide 1-stimulated postprandial insulin secretion in humans. Diabetes, 60 (9), 2308-14 PMID: 21868791

Holst JJ (2011). Postprandial insulin secretion after gastric bypass surgery: the role of glucagon-like Peptide 1. Diabetes, 60 (9), 2203-5 PMID: 21868790

Regular readers of these pages, will by now know that bariatric surgery is by far the most effective and reliable treatment for severe obesity.

However, how exactly bariatric surgery works, continues to be an intense field of medical and experimental research.

Last year, this was the topic of the 13th Bariatric/metabolic International Symposium of the Merck Frosst/CIHR Research Chair in Obesity at Laval University, the proceeding of which have now been published in a supplement to the International Journal of Obesity.

As pointed out by Keith Sharkey, from the University of Calgary, in an accompanying editorial,

“surgeries are remarkably effective in reducing weight over a sustained period of time, and they also have significant beneficial effects on glucose homeostasis. Interestingly, the metabolic benefits of these surgeries frequently occur before significant weight loss.”

Studies in this supplement use animal models to reveal the neurohumoral mechanisms underlying weight loss and improved glucose homeostasis after experimental bariatric surgery.

Not only do these rodent models of bariatric surgery show that food reward is altered and that the proximal gut is important in the control of energy balance and glucose homeostasis, but these studies provide important insights into the molecular and neuronal mechanisms of these effects.

Of course, from my perspective, the hope is that there findings will eventually lead to pharmaceutical approached to treating severe obesity that will eventually put bariatric surgeons out of business.

Till then, we must accept that surgical treatment is far more effective for managing severe obesity in patients, who urgently need treatment, than any conservative ‘Eat-Less-Move-More’ approaches have to offer.

Of course, preventing the obesity in the first place would be even better, but that certainly does not solve the problem of the tens of thousands, who cary 100s of excess pounds and have few, if any, other options to deal with their considerable excess weight and related health problems.

AMS
Edmonton, Alberta

Sharkey KA (2011). Animal models of bariatric/metabolic surgery shed light on the mechanisms of weight control and glucose homeostasis: view from the chair. International journal of obesity (2005), 35 Suppl 3 PMID: 21912385