Thursday, April 10, 2014

Managing Weight Loss Expectations

sharma-obesity-great-expectationsWhile there are almost no limits to short-term weight loss goals (anyone can starve themselves thin) – the reality of long-term weight loss is rather sobering.

While diet and exercise generally provide an average long-term (3-5 years) sustainable weight loss or about 3-5% of initial weight, even bariatric surgery patients tend on average to sustain a weight loss of only 20-30% of their initial weight.

Surgery, although much safer than generally thought, still bears a risk of complications and the question is how much risk patients are willing to assume if they really knew and understood how much weight they are likely to lose with surgery.

This was the subject of a study by Christina Wee and colleagues, published in JAMA Surgery, in which they examined weight loss expectations and willingness to accept risk among patients seeking bariatric surgery.

The researchers interviews 650 patients interested in bariatric surgery at two bariatric centres in Boston.

On average, patients expected to lose as much as 38% of their weight after surgery and expressed disappointment if they did not lose at least 26%.

In fact, 40% of patients were unwilling to undergo a treatment that would result in only 20% weight loss.

Most patients (85%) accepted some risk of dying to undergo surgery, but the median acceptable risk was only 0.1%.

On the other hand, some patients (20%) appeared more desperate, willing to accept a risk of 10% or greater.

As one may expect, there were important gender differences in these findings: while women were more likely than men to be disappointed with a 20% weight loss, they were also less likely to accept a greater mortality risk.

An important finding for clinicians was that patients with lower quality-of-life scores and those who perceived needing to lose more than 10% and 20% of weight to achieve “any” health benefits were more likely to have unrealistic weight loss expectations.

This study not only shows that most patients seeking bariatric surgery have rather unrealistic weight loss expectations but also that   a substantial number may well be be disappointed with their weight loss after surgery.

It is also evident that many patients believe that they need to lose a rather substantial amount of weight to derive “ANY” health benefits, when in reality even rather modest (and certainly the average 20-30% weight loss seen with surgery) carries substantial health benefits for patients. (Many patients would in fact benefit substantially if they simply stopped gaining weight).

I certainly wonder what educational efforts may be necessary to align expectations with the clinical reality of bariatric surgery and whether better managing expectations is likely to alter current practice?

@DrSharma
Edmonton, AB

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Wednesday, April 9, 2014

Reserve Your Spot At The Obesity and Mental Health Conference, Toronto, May 14, 2014

smaller_CON_OMH_program_2014_2_Page_014614As a regular reader you may recall a previous conference on obesity and mental health which saw the release of the Toronto Charter on Obesity and Mental Health.

A follow up to this conference will be held in Toronto on May 14, 2014.

This time the focus is on clinical management of people with mental health issues presenting with weight gain as well as people with obesity presenting with mental health problems.

This one-day program features a rather distinguished roster of speakers, the full program can be downloaded here.

Registration for the conference is now open to all health professionals with an interest in obesity and/or mental health – click here

For more information on this conference – click here

@DrSharma
Edmonton, AB

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Monday, April 7, 2014

The Molecular Mechanism of Sleeve Gastrectomy

sharma-obesity-verticalsleevegastrectomyIn recent year, vertical sleeve gastrectomy (VSG), which involves removing large parts of the stomach, thereby reducing it to the size of a small banana, has gained in popularity in bariatric surgery.

Although slightly less efficacious, it is a far simpler procedure to perform than the “classic” Roux-en-Y gastric bypass.

According to popular wisdom, the reason why VSG works has to do with mechanically reducing the volume of the stomach (thereby creating a physical “restriction”), whereby effect on gastric ghrelin secretion may or may not also play a role in reducing hunger (the science on this is somewhat unclear).

Now, a paper by Karen Ryan and colleagues from the University of Cincinnati, published in Nature, provides a completely new explanation for the molecular mechanism by which this surgery appears to work.

The study was prompted by the observation that VBG leads to profound changes in circulating bile acids. Bile acids are now known to bind to a nuclear receptor (farsenoid-X-receptor or FXR for short) which plays an important role in fat and glucose metabolism.

Using a rather elegant series of studies in mice, Ryan and colleagues demonstrate that the weight loss effect of sleeve gastrectomy has little to do with reducing the size of the stomach. Rather, almost all of its effect on body weight appears to be mediated by the effect of this surgery on circulating bile acids and accompanying changes in gut microbial flora.

The researchers also clearly demonstrate that much of the weight loss with SVG is dependent on a functional FXR, without which (as in FXR knockout mice) the surgery has little effect on body weight or glucose metabolism.

This demonstration of the importance of bile acids and FXR signalling as an important molecular mechanism for why VSG actually works is important because it means that this surgery could possibly be mimicked by pharmacological interventions that target bile acid and/or FXR.

In fact drugs that stimulate FXR (e.g. obeticholic acid) are already being considered for other indications including fatty liver disease and type 2 diabetes.

Given the remarkable efficacy of VSG surgery, the possibility of providing the same benefits in a pill are clearly attractive.

@DrSharma
Edmonton, AB

ResearchBlogging.orgRyan KK, Tremaroli V, Clemmensen C, Kovatcheva-Datchary P, Myronovych A, Karns R, Wilson-Pérez HE, Sandoval DA, Kohli R, Bäckhed F, & Seeley RJ (2014). FXR is a molecular target for the effects of vertical sleeve gastrectomy. Nature PMID: 24670636

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Wednesday, April 2, 2014

Trotting Out STAMPEDE

sharma-obesity-blood-sugar-testing2In the obesity world, this week’s big news is the publication of the three year results of the STAMPEDE trial in the New England Journal of Medicine.

As a regular reader, you may recall my previous post on this randomised controlled trial of bariatric surgery for the treatment of type 2 diabetes.

STAMPEDE involved the randomisation of 150 obese patients with uncontrolled type 2 diabetes to either intensive medical therapy alone or intensive medical therapy plus Roux-en-Y gastric bypass or sleeve gastrectomy.

Rather than weight loss, the primary end point of STAMPEDE was a glycated hemoglobin (HbA1C) level of 6.0% or less (from a mean baseline of 9.3%).

For the 91% of the patients who completed 36 months of follow-up at three years, 5% of the patients in the medical-therapy group achieved an HbA1c of 6.0% compared to 38% of those in the gastric-bypass group and 24% of those in the sleeve-gastrectomy group.

In addition, surgically treated subjects overall had far lesser need for glucose-lowering medications, including insulin than those receiving medical treatment.

Weight was reduced by 20-25% in the surgical groups compared to a 4% weight loss in the medical arm of the study.

Quality-of-life was also significantly better in the two surgical groups than in the medical-therapy group.

There were no major late surgical complications.

By any reasonable standard, there cannot be any remaining doubt in anyone’s mind that surgical treatment for type 2 diabetes is vastly superior to anything that medical treatment has to offer.

Diabetologists and, in fact, all physicians, diabetes educators, dietitians and other health professionals, who fail to inform and counsel their type 2 patients with regard to surgical treatment options for their condition, risk being accused of malpractice.

Whether patients want surgery for diabetes or not is ultimately their choice – being informed of the potential benefits of surgery should not be a matter of choice – it should be good clinical practice.

@DrSharma
Edmonton, AB

Disclaimer: I am NOT a surgeon!

ResearchBlogging.orgSchauer PR, Bhatt DL, Kirwan JP, Wolski K, Brethauer SA, Navaneethan SD, Aminian A, Pothier CE, Kim ES, Nissen SE, Kashyap SR, & the STAMPEDE Investigators (2014). Bariatric Surgery versus Intensive Medical Therapy for Diabetes – 3-Year Outcomes. The New England journal of medicine PMID: 24679060

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Monday, March 17, 2014

Why There Is HOPE For The NFL

sharma-obesity-footballA sad consequence of professional athleticism are the many health hazards associated with competitive sports.

This also applies to US National Football League (NFL) players, particularly to linesmen, who have a markedly increased risk for excessive weight gain with all the metabolic and physical health consequences commonly seen in obese individuals.

This is now of so great a concern, that the US Living Heart Foundation has created the Heart, Obesity, Education, Prevention (HOPE) program dedicated to screening former National Football League (NFL) players for health, in particular cardiovascular health, problems.

As described by George Buchwald, in an article published in SOARD, the mission of HOPE is two fold:

(1) Screening of former NFL players focused on obesity and the obesity comorbidities with referral of selected players on a voluntary basis to a regional center of excellence for further assessment and therapy.

(2) Recruiting successfully managed players as emissaries to the general public to discuss the diagnosis, prevention, and treatment of obesity and the obesity comorbidities.

Buchwald is particularly enthusiastic about the latter, as professional athletes have hero status and command the attention of the public – this could be a natural conduit for health messages.

The LIFE HOPE program also offers treatments to NFL players for their obesity, including diet, exercise, behavior modification, pharmaceuticals, and metabolic/bariatric surgery.

Of note, the program is a partnership between the NFL, the Living Heart Foundation and Covidien, a leading maker of devices for bariatric surgery.

Whether or not this approach to recruiting (former) elite athletes with obesity to promote health messages (including promoting bariatric surgery) bears fruit remains to be seen.

I wonder what you think about this initiative.

@DrSharma
Edmonton, AB

 

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In The News

Diabetics in most need of bariatric surgery, university study finds

Oct. 18, 2013 – Ottawa Citizen: "Encouraging more men to consider bariatric surgery is also important, since it's the best treatment and can stop diabetic patients from needing insulin, said Dr. Arya Sharma, chair in obesity research and management at the University of Alberta." Read article

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