Another series of articles in the 2018 JAMA special issue on obesity, deals with the impact of bariatric surgery on health outcomes and overall mortality.
The first article by Sayeed Ikramuddin and colleagues is an observational follow-up of a randomized clinical trial at 4 sites in the United States and Taiwan, involving 120 participants who had a hemoglobin A1c(HbA1c) level of 8.0% or higher and a BMI between 30.0 and 39.9. The study compared intensive lifestyle and medical management intervention based on the Diabetes Prevention Program and LookAHEAD trials for 2 years, with and without (60 participants each) Roux-en-Y gastric bypass surgery followed by observation to year 5.
At 5 years, 13 participants (23%) in the gastric bypass group and 2 (4%) in the lifestyle-intensive medical management group had achieved the composite triple end point (HbA1c less than 7.0%, LDL cholesterol less than 100 mg/dL, and systolic blood pressure less than 130 mm Hg).
In the fifth year, 31 patients (55%) in the gastric bypass group vs 8 (14%) in the lifestyle–medical management group achieved an HbA1c level of less than 7.0%.
As is to be expected, surgical treatment resulted in more serious adverse events (66 vs 38 events), most frequently involving gastrointestinal and surgical complications such as strictures, small bowel obstructions, and leaks.
A second study by Gunn Signe Jakobsen and colleagues from Norway, reports on changes in obesity related comorbidities in patients with severe obesity (BMI ≥40 or ≥35 and at least 1 comorbidity) undergoing bariatric surgery (n=932, 92 gastric bypass) or specialized medical (“lifestyle”) treatment (n=956) at a tertiary care outpatient center.
Based on drugs dispensed according to the Norwegian Prescription Database and data from the Norwegian Patient Registry and a local laboratory database, surgically treated patients had a greater likelihood of remission (RR, 2.1) and lesser likelihood for new onset of hypertension (RR, 0.4), a greater likelihood of diabetes remission (RR, 3.9) but also a greater risk of new-onset depression (RR, 1.5) and treatment with opioids (RR, 1.3.
Again, as expected, surgical patients had a greater risk for undergoing at least 1 additional gastrointestinal surgical procedure (RR, 2.0).
From these findings the researchers conclude that adding gastric bypass to lifestyle and intensive medical management alone in patients with severe obesity and type 2 diabetes, there remained a significantly better composite triple end point in the surgical group at 5 years.
The third study by Orna Reges and colleagues from Israel, was a retrospective cohort study in a large Israeli integrated health fund database, that compared 8,385 patients who underwent bariatric surgery compared to 25,155 nonsurgical patients matched on age, sex, BMI, and diabetes. The surgical interventions included laparoscopic banding [n = 3635], gastric bypass [n = 1388], and laparoscopic sleeve gastrectomy [n = 3362]
Over the approximately 4.5-year follow up period, there were 105 deaths (1.3%) among surgical patients compared to 583 deaths (2.3%) among nonsurgical patients.
Mortality rates were similar across the different types of surgery: [1.7%] who underwent laparoscopic banding, 18 [1.3%] gastric bypass, and 26 [0.8%] sleeve gastrectomy).
Form these findings the authors conclude that, compared with usual care, nonsurgical obesity management, was associated with lower all-cause mortality.
Finally, a fourth paper by Sarah Shubeck and colleagues from the University of Michigan, discuss the finding of a study by Anita Courcoulas and colleagues published in JAMA Surgery, which describes 7-year weight trajectories and health outcomes in the Longitudinal Assessment of Bariatric Surgery (LABS) Study that includes 1738 patients who underwent Roux-en-Y gastric bypass (RYGB) and 610 patients who underwent laparoscopic adjustable gastric banding (LAGB).
At 7 years, patients who had undergone RYGB lost 28% of initial weight with minimal weight regain between years 3 and 7 (3.9%) compared to patients who had undergone LAGB (14.9% weight loss with 1.4% regain).
Patients who had undergone RYGB benefitted from high rates of long-term relief from all 5 comorbidities evaluated (diabetes mellitus, high LDL cholesterol, high triglycerides, low HDL cholesterol level, and hypertension) at 7 years than those who had undergone LAGB.
Importantly, postprocedure mortality was very low with 3 deaths within 30 days of surgery and 7-year death rates of 3.7/700 person-years after RYGB (59 deaths) and 2.7/700 person-years after LAGB (15 deaths). Rates of operative revisions and reversals were low for patients in the RYGB group (0.92/700 person-years), but were significantly higher among patients in the LAGB group (30.29/700 person-years).
Taken together, all 4 studies document the considerable long-term health benefits associated with surgical treatment of severe obesity but also note that there are certain surgical risks (which vary between procedures) that need to be individually discussed with patients.
In the 2018 special issue of JAMA on obesity, two research articles compare long-term outcomes (5 years) after laparoscopic roux-en-Y gastric bypass (RYG) to sleeve gastrectomy (SG).
In the first study by Ralph Peterli and colleagues from Switzerland, the authors report on the findings from the Swiss Multicenter Bypass or Sleeve Study (SM-BOSS), a 2-group randomized trial, that included 217 patients at 4 bariatric centres, who were enrolled and randomly assigned to SG or RYG.
At 5 years, weight loss was slightly greater in the RYG group but this difference was not statistically significantly.
Gastric reflux improved more after RYG and was more likely to worsen with SG. Reoperation rates were marginally higher in the RYG group (seven reoperations after sleeve gastrectomy were for severe GERD, and 17 reoperations after bypass were for internal hernias) .
In the second study Paulina Salminen and colleagues from Finland report on the Sleeve vs Bypass (SLEEVEPASS) multicenter, multisurgeon, open-label, randomized clinical equivalence trial which randomly assigned patients with severe obesity to SG (n=121) or RYG (n=119) with a 5-year follow-up period.
At 5 years, weight loss, remission of diabetes, as well as improvements in dyslipidemia and hypertension were slightly higher in the RYG group than in the SG group.
Overall, there was no difference in improvement in quality of life or in morbidity rates between the two groups. There was no treatment-related mortality in either group.
In an accompanying editorial, David Arterburn and Arniban Gupta from the University of Washington, Seattle, note that,
“Collectively, these studies provide reassuring data to suggest that the rapid switch from Roux-en-Y gastric bypass to sleeve gastrectomy in the last decade has not been a therapeutic misadventure similar to the rise and fall of the adjustable gastric band,5 which has been all but abandoned.”
They also point to five important learnings from these studies:
- Patients should be informed that deciding between sleeve gastrectomy and bypass is complex and requires patients to simultaneously consider information about many factors, including weight loss, control of different comorbidities, and short- and long-term risks.
- Weight loss between the two procedures are more or less on par.
- GS may be a reasonable choice even for patients with diabetes.
- Patients with GERD deserve careful consideration, because their outcomes are differentially affected by sleeve gastrectomy and gastric bypass.
- Given the relative parity between these procedures in weight loss and comorbidity resolution, shared decision making conversations should prioritize discussion of individual risk tolerance and preferences, ie, which potential risk or consequence is more acceptable to the patient—the risk of reoperation for GERD with sleeve gastrectomy vs the risk of reoperation for a small bowel obstruction or internal hernia with bypass.
Ultimately, deciding between the two procedures is not easy and warrants an in-depth discussion between patients and their surgeons.
This week, JAMA revisits obesity with a dedicated theme issue, which includes a range of articles on obesity prevention and management (including several on the impact of taxing sugar-sweetened beverages and five original long-term studies on bariatric surgery).
In an accompanying editorial, Edward Livingston notes that,
“The approach to the prevention and treatment of obesity needs to be reimagined. The relentless increase in the rate of obesity suggests that the strategies used to date for prevention are simply not working.”
“From a population perspective, the increase in obesity over the past 4 decades has coincided with reductions in home cooking, greater reliance on preparing meals from packaged foods, the rise of fast foods and eating in restaurants, and a reduction in physical activity. There are excess calories in almost everything people eat in the modern era. Because of this, selecting one particular food type, like SSBs, for targeted reductions is not likely to influence obesity at the population level. Rather, there is a need to consider the entire food supply and gradually encourage people to be more aware of how many calories they ingest from all sources and encourage them to select foods resulting in fewer calories eaten on a daily basis. Perhaps tax policy could be used to encourage these behaviors, with taxes based on the calorie content of foods. Revenue generated from these taxes could be used to subsidize healthy foods to make them more affordable.”
Over the next few days, I will be reviewing about the individual articles and viewpoints included in this special issue.
In the meantime, the entire issue is available here.
Registration and Abstract submission for the Canadian Obesity Network’s 6th biennial Canadian Obesity Student Meeting (COSM), June 20-22, London, Ontario, is now open.
As attendees of past COSMs will be well aware, this is a pretty unique meeting organised entirely by the Canadian Obesity Network’s Student and New Professional (CON-SNP) network, open to 200 MSc/PhD students, young researchers, post-docs, clinical fellows, clinical researchers and young health professionals in their last, or within five years of, completing their training.
As in previous years, we expect attendance not just from across Canada but also the US, Mexico, and overseas.
The meeting will highlight important advances in obesity research and provide important opportunities for new professionals and trainees to present findings and network with their peers.
The presentations and discussions will range from cellular and molecular biology to childhood obesity, primary intervention, and population health.
However, the primary purpose of this meeting is to enhance student growth and development with ample opportunity to network and get to know your peers.
For more information on how to submit and abstract (deadline March 5) and to register for COSM 2018 click here
This week, the Canadian Obesity Network in partnership with mdBriefCase has launched a series of online learning modules for health professionals. This is part of the Network’s ongoing international initiative to create accredited learning resources on obesity management in primary and is closely aligned with the 5As of Obesity Management which are now available in Canada, Brazil, Italy, Denmark, Germany, Finland and Norway.
These modules are available for free using the links below. (If you don’t already have an account, you will be asked to register but registration is free!)
An Ounce of Prevention: Medical Management of Obesity-Related Comorbidity
Meet Marion. Marion is 28 years of age, and has been struggling with her weight. Marion’s main concern about her weight has to do with her appearance and how she is received socially.
Canadian Physician Module CLICK HERE
Canadian Allied Health Module CLICK HERE
Halting Obesity Progression
Meet Robert. Robert is 19 years of age and has struggled with being overweight since childhood. He has a family history of diabetes on both sides. Robert recently lost 10kg, but was unable to sustain the weight loss.
Canadian Physician Module CLICK HERE
Canadian Allied Health Module CLICK HERE
Sleep Debt in Adult Obesity in Brazil: A Critical Factor Often Overlooked
Obesity is associated with many forms of sleep disruption due to a variety of causes including, for example, body pain, disrupted circadian rhythms, depression or snoring and other breathing-related sleep problems.
Brazilian healthcare practitioners – CLICK HERE
All other international healthcare practitioners – CLICK HERE
It is no secret that access to evidence-based obesity treatments is difficult for most Canadians living with obesity. This includes both access to knowledgeable multi-disciplinary chronic disease programs with experience in long-term obesity management and coverage for obesity medications.
Because advocacy is most effective when people living with obesity (and their families) themselves get engaged in demanding better access and services, the Canadian Obesity Network has now released fact sheets with guidance for patients seeking to advocate for themselves.
These information sheets are available both in English and French and can be downloaded at the following links:
The assessment of weight history is no doubt a key feature of obesity assessment. Not only can weight history and trajectories provide important insights into obesity related risk but, perhaps more importantly, provide key information on precipitating factors and drivers of excessive weight gain.
Now, in a short article published in MedEdPublish, Robert Kushner discusses how the well-known OPQRST mnemonic for assessing a “chief complaint” can be applied to assess body weight.
In short, OPQRST is a mnemonic for Onset, Precipitating, Quality of Life, Remedy, Setting, and Temporal pattern. Applied to obesity, Kushner provides the following sample questions for each item:
Onset: “When did you first begin to gain weight?” “What did you weight in high school, college, early 20s, 30s, 40s?” “What was your heaviest weight?”
Precipitating: “What life events led to your weight gain, e.g., college, long commute, marriage, divorce, financial loss?” “How much weight did you gain with pregnancy?” “How much weight did you gain when you stopped smoking?” “How much weight did you gain when you started insulin?”
Quality of life: “At what weight did you feel your best?” “What is hard to do at your current weight?”
Remedy: “What have you done or tried in the past to control your weight?” “What is the most successful approach you tried to lose weight?” “What do you attribute the weight loss to?” “What caused you to gain your weight back?”
Setting: “What was going on in your life when you last felt in control of your weight?” “What was going on when you gained your weight?” “What role has stress played in your weight gain?” “How important is social support or having a buddy to help you?”
Temporal pattern: “What is the pattern of your weight gain?” “Did you gradually gain your weight over time, or is it more cyclic (yo-yo)?” “Are there large swings in your weight, and if so, what is the weight change?”
As Kushner notes,
“These features provide a contextual understanding of how and when patients gained weight, what efforts were employed to take control, and the impact of body weight on their health. Furthermore, by using a narrative or autobiographical approach to obtaining the weight history, patients are able to express, in their own words, a life course perspective of the underlying burden, frustration, struggle, stigma or shame associated with trying to manage body weight. Listening should be unconditional and nonjudgmental. By letting patients tell their story, the clinician is also able to assess the patients’ awareness, knowledge, motivation, decision-making, and resiliency regarding weight management. The narrative provides a basis for approaching the patients’ weight holistically, as well as beginning to formulate diagnostic and therapeutic options.”
There is no doubt much to be gained in understanding obesity by allowing patients to tell their own weight stories.
In my talks, I have often joked about how to best keep weight off – just carry around a backpack that contains the lost pounds to fool the body into thinking the weight is still there.
It turns out that what was intended as a joke, may in fact not be all too far from how the body actually regulates body weight.
As readers of these posts are well aware, body weight is tightly controlled by a complex neuroendocrine feedback system that effectively defends the body against weight loss (and somewhat, albeit less efficiently, protects against excessive weight gain).
Countless animal experiments (and human observations) show that following weight loss, more often than not, body weight is regained, generally precisely to the level of initial weight.
With the discovery of leptin in the early 90s, an important afferent part of this feedback system became clear. Loss of fat mass leads to a substantial decrease in leptin levels, which in turn results in increased appetite and decreased metabolic rate, both favouring weight regain and thus, restoration of body weight to initial levels.
Now, an international team of researchers led by John-Olov Jansson from the University of Gothenburg, Sweden, in a paper published in the Proceeding of the National Academy of Science (PNAS), provides compelling evidence for the existence of another afferent signal involved in body weight regulation – one derived from weight-bearing bones.
Prompted by observations that prolonged sedentariness can promote weight gain, independent of physical activity, the researchers hypothesised that,
“…there is a homeostat in the lower extremities regulating body weight with an impact on fat mass. Such a homeostat would (together with leptin) ensure sufficient whole body energy depots but still protect land-living animals from becoming too heavy. A prerequisite for such homeostatic regulation of body weight is that the integration center, which may be in the brain, receives afferent information from a body weight sensor. Thereafter, the integration center may adjust the body weight by acting on an effector.”
In a first series of experiments, the researchers observed that implanting a weight corresponding to about 15% of body weight into rodents (rats and mice), resulted in a rapid “spontaneous” adjustment in body weight so that the combined weight of the animal plus the weight implant corresponded more-or-less to that of control animals.
Within two weeks of implanting the weights, ∼80% of the increased loading was counteracted by reduced biological weight, largely due to reduced white adipose tissue (WAT), accompanied by a corresponding decrease in serum leptin levels. (Interestingly, this weight loss was also accompanied by a substantial improvement in insulin resistance and glucose homeostasis).
The decrease in “biological” body weight was mainly attributable to a reduction in caloric intake with no changes in fat oxidation, energy expenditure or physical activity.
Removal of the implanted weights resulted in rapid weight regain to initial levels, showing that the “weight sensor” was active in both directions.
Experiments showed that this “weight sensing” mechanism was largely independent of the leptin pathway and did not appear to involve grehlin, GLP-1, a-MSH, estrogen receptor-a, or the sympathetic nervous system.
Now for the interesting part: the observed effect of weight loading was not seen in mice depleted specifically of DMP1 osteocytes, demonstrating that the suppression of body weight by loading is dependent on osteocytes.
As the authors note, these findings are consistent with a growing body of data indicating that the skeleton is an endocrine organ that regulates energy and glucose metabolism. Indeed, it is well known that osteocytes can sense dynamic short term high-impact bone loading for local bone adaptation – now it appears, that osteocytes may also play a vital role in sensing overall body weight and signalling this to the brain centres that regulate energy balance and body weight.
Thus, in summary, not only have the authors provided compelling evidence for a “weight-sensing” role for bone osteocytes (presumably through their presence in the long weight-bearing bones of our lower extremities) but also provide a plausible biological explanation for the weight gain and change in fat mass seen with prolonged sedentariness (which literally takes the weight off the bone).
These findings may also finally explain why rats held at increased gravity for extended periods of time (simulated G2) become lean even when their energy intake matches their expenditure.
Perhaps, carrying around a heavy backpack may indeed help with long-term weight loss maintenance after all – who knew?
Hat tip to Jean-Philippe Chaput for alerting me to this article