Dr. Sharma's Obesity Notes

This Month’s edition of Canadian Family Physician, the official journal of the College of Family Physicians of Canada, features a debate on whether or not family doctors should stop telling their patients to lose weight.

On the Pro side, we have Jana Havrankova, an endocrinologist at Clinique familiale Saint-Lambert in Quebec, notes that keeping weight off is anything but simple.

“The few patients who manage to lose weight and keep it off achieve something truly remarkable. From a public health standpoint, however, the treatment of obesity is a failure.“

Thus, rather than trying to treat obesity, Havrankova places her bets on prevention:

“Efforts at prevention involve some degree of telling people what to do, and some people will criticize this. Screening and monitoring excess weight from early childhood, ensuring that physical activity is part of the curriculum right up to university, creating neighbourhoods that encourage people to get out and walk, and teaching people how to prepare healthy meals are just a few suggestions.”

In the Contra corner we have Dominique Garrel, a specialist in endocrinology and metabolism and Full Professor in the Department of Nutrition at Université de Montréal, Quebec.

Not only does Garrel argue that obesity must be treated, but also that the treatment of obesity can be simple and effective. However, treatment needs to focus on health and not on weight loss.

“Treat the patient, not his weight. Telling an obese patient to lose weight is about as effective as telling an asthmatic patient to breathe better! Care consists of assessing the risks of excess weight to a patient’s health. The Edmonton Obesity Staging System recently proposed by Kuk et al [sic] is an interesting tool designed for this point of view. This system includes recommendations for each level of intervention, ranging from simply recommending that the patient maintains his weight, to recommending bariatric surgery.”

He also points out the importance of recognising and treating comorbidities as these may often represent roadblocks to weight management, to set reasonable (read ‘modest’) objectives for weight loss, and inform the patient of the tools at his disposal for losing weight (as well as warn them against unhealthy weight loss efforts).

In an accompanying editorial, Roger Ladouceur, Associate Scientific Editor of CFP, notes the following:

“Why, then, do we tell our patients to lose weight? Why do we repeat, “You should lose weight”? What’s with that? Somewhat sadistic, don’t you think? Do we do this as a way of shifting the guilt and transferring the responsibility of the therapeutic failure?”

In fact, Ladouceur concludes with the rather profound statement that:

“All things considered, shouldn’t we put a stop to this preoccupation with our patients’ weight and simply encourage them to develop healthy lifestyle habits, to adopt a balanced diet, to practise on a regular basis any form of exercise that they enjoy, even if it is simply walking? Instead of repeating “You should lose weight,” shouldn’t we help them to become more comfortable with themselves?”

Although this statement may not at all sound ‘profound’ to regular readers of these pages, such an ‘insight’ printed in the ‘house journal’ of the CFPC, which goes out to every family doctor in Canada, represents a major step forward in our thinking about obesity - if anything, it certainly moves right into the mainstream of what the Canadian Obesity Network’s experts and Family Practice Group has been saying all along (and is about to promote with a nationwide program due to be released in the next few days).

Not only am I happy to see promotion of the Edmonton Obesity Staging System, but am also particularly pleased to see that both sides (and the editorial) are seeing health as being more than just numbers on the scale.

Neither suggests we ignore obesity or that it does not confer health risks - but they do suggest that it is time to radically rethink the traditional “lose weight and you’ll be fine” approach based on the simplistic notion of “eat-less move-more”.

Incidentally, this debate and editorial accompanies another article in this edition of CFP with the title: “The Downside of Weight Loss” - more on this paper in tomorrow’s post.

AMS
Grand Prairie, Alberta

Hat tip to the Canadian Obesity Network’s Primary Practice Working Group member Dr. Shahebina Walji, Calgary, for alerting me to these articles.

Bariatric surgery can profoundly affect how the body absorbs medications - this issue, however, remains largely understudied.

In a paper, just published in the Journal of Antimicrobial Chemotherapy, we examine the effect of gastric bypass surgery, a procedure that circumvents the upper gut on the bioavailability (absorption) of azithromycin, a widely used treatment for community-acquired infections.

We performed single-dose pharmacokinetic studies in 14 female post-gastric bypass patients and 14 sex- and body mass index (BMI)-matched controls (mean age 44 years and BMI 36.4).

Azithromycin concentrations, following the administration of two 250 mg tablets were about 30% lower in gastric bypass patients compared with controls.

This finding suggests that there may be a substantial risk for treatment failure with this antibiotic in and clinicians should consider dose modification and/or closer clinical monitoring of gastric bypass patients receiving azithromycin.

AMS
Calgary, Alberta

Padwal RS, Ben-Eltriki M, Wang X, Langkaas LA, Sharma AM, Birch DW, Karmali S, & Brocks DR (2012). Effect of gastric bypass surgery on azithromycin oral bioavailability. The Journal of antimicrobial chemotherapy PMID: 22577100

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Relative Size Illusion

Regular readers may recall previous posts on the widespread reporting of weight loss in surgical studies as ‘excess weight loss’ - a meaningless number based on outdated concepts of ‘ideal weight’. In fact, not only is there is little correlation between the amount of weight lost and improvements in post-surgical morbidity and mortality but there is nothing to suggest that using this measure does anything more than amplify the numbers - after all a rather remarkable 60% EWL is little more than 20% of initial weight - but of course 60% sounds so much better.

I was therefore happy to see that last week, at the FDA hearing on obesity devices, according to Close Concerns:

“There was nearly unanimous support for using percentage of total body weight rather than percentage of excess weight loss as a study endpoint. Panelists cited the “significant flaws” in excess weight loss, especially the challenge of applying it to individuals with lower BMIs. In contrast, many believed that using percentage of total body weight loss provided a more valid metric for people at both high and low BMIs.”

Hopefully, surgeons and surgical device makers will take note and comply with what I am hoping the FDA will from now on like to see in all future submissions - strict reporting of percentage of ‘total weight loss’ rather than the confusing, arbitrary, and scientifically unsound use of ‘excess weight loss’, which I fear the surgeons may find hard to abandon.

AMS
Brooks, Alberta

As not everyone may have a chance during the week to read every post, here’s a roundup of last week’s posts:

• Removing the Cause of Weight Gain Does Not Mean Weight Loss
• Why Stopping Weight Gain is More Important Than Losing Weight
• Institute of Medicine Big on BMI, Eat Less and Move More
• Challenges in the Medical Management of Severe Obesity
• European Joint Statement on Obesity and Hypertension

Have a great Sunday! (or what is left of it)

AMS
Edmonton, Alberta

Given our interest in the renin angiotensin system (RAS) in adipose tissue, in the early 2000s, my lab back in Berlin was studying the effect of how this system affects the growth and differentiation of cultured human fat cells.

Other laboratories had suggested that angiotensin II (Ang II) plays a role in the differentiation of preadipocytes into mature adipocytes in mouse cell lines. We wanted to explore if the same was true for human cells

So we performed a series of experiments, in which we isolated preadipocytes from human adipose tissue and exposed them to angiotensinogen (AGT), Ang II, or angiotensin receptor antagonists in the differentiation medium. We found that the expression of the RAS genes AGT, renin, angiotensin-converting enzyme, and Ang II type 1 receptor increased during adipogenesis.

To our surprise, we also found that stimulation of the Ang II type 1 receptor by Ang II reduced adipose conversion, whereas blockade of this receptor markedly enhanced adipogenesis.

Assuming that the angiotensinogen formed by mature adipocytes may perhaps directly affect preadipocyte differentiation, we performed co-culture experiments, where we were able to show that mature adipocytes were indeed able to inhibit preadipocyte differentiation, an effect that was almost entirely abolished by blockade of the Ang II type 1 receptor.

In our paper, published in DIABETES, we not only interpreted these findings as indicative of a functional role of the RAS in the differentiation of human adipose tissue but also postulated that a paracrine negative-feedback loop, which inhibits further recruitment of preadipocytes by maturing adipocytes may be an important mechanisms in regulating adipose tissue growth and expansion.

These findings subsequently prompted us (and several other laboratories) to further explore the role of this system in adipose tissue, including studies in animal models and humans.

According to Google Scholar, this paper has been cited 242 times.

AMS
Lyon, France