How Precise Can Obesity Medicine Get?
Another article in the 2018 JAMA special issue on obesity is one by Susan and Jack Yanovski and deals with the issue of using a precision or “personalised” approach to obesity prevention and management. As we know, there are myriad factors that can lead to obesity (environmental, genetic, psychological, medical, etc., etc., etc.), with each patient having their own story and set of drivers and barriers. Furthermore, we know that for any given treatment (whether behavioural, medical, or surgical) there is wide variation in individual outcomes. So, being able to match the right treatment to the right patient, or even better, reliably predict a given patient’s response to a specific treatment could potentially improve outcomes and reduce patient burden and costs. However, as the authors note, currently the only real predictor to treatment response is how well patients respond during the early part of treatment. Thus, we know that patient who lose a significant amount of weight during the first few weeks of medical treatment, tend to have the best long-term success in terms of weight loss. However, this approach is also rather limited. In my own practice, I regularly see patients, who initially do well with behavioural, medical or surgical treatments, but eventually struggle, as well as patients who take longer to respond to a treatment before ultimately doing fine in the long term. We are of course a long way off from having any kind of genetic or other testing that would reliably predict patient responses to treatment. While this may become possible in the future, I am not holding my breath. Not only is every patient’s story different, but the many factors that can determine response (societal, behavioural, psychological, biological, etc.) are almost endless and, moreover, can even vary over time in a given individual. In fact, for most complex chronic diseases (e.g. diabetes, hypertension, depression, etc.), finding the best treatment for a given patient continues to be “trial and error”, or in other words, “empirical”. Despite all the progress in genetic research, this has not really changed for most other complex chronic diseases like hypertension, type 2 diabetes, or dyslipidemia (despite a few rare but notable exceptions). Moveover, as the authors point out, there are many other factors that will determine whether or not a given patient even has access to certain treatments, irrespective of whether or not that treatment is indeed the best treatment for… Read More »
Counting Calories For Weight Loss – More of The Same
If there is one article in the 2018 special issue of JAMA on obesity that we could have well done without, it is surely the one by Eve Guth promoting the age-old notion that simply counting calories is a viable and effective means to manage body weight. As the author suggests: “It is better for physicians to advise patients to assess and then modify their current eating habits and then reduce their caloric ingestion by counting calories. Counseling patients to do this involves provision of simple handouts detailing the calorie content of common foods, suggested meal plan options, an explanation of a nutrition label, and a list of websites with more detailed information. Patients should be advised that eating about 3500 calories a week in excess of the amount of calories expended results in gaining 1 lb (0.45 kg) of body weight. If a patient reduces caloric ingestion by 500 calories per day for 7 days, she or he would lose about 1 lb of body weight per week, depending on a number of other factors. This is a reasonable and realistic place to start because this approach is easily understood and does not ask a patient to radically change behavior.” There is so much wrong with this approach, that it is hard to know exactly where to start. For one, this advise is based on the simplistic assumption that obesity is simply a matter of managing calories to achieve and sustain long-term weight loss. Not only, do we have ample evidence that these type of approaches rarely result in long-term sustained weight-loss but, more importantly this type of advice comfortably ignores the vast body of scientific literature that tells us that body weight is a tightly regulated physiological variable and that there are a host of complex neuroendocrine responses that will defend our bodies against long-term weight loss – mechanisms that most people (irrespective of whether they have obesity or not) will find it exceedingly hard to overcome with “will-power” alone. No doubt, caloric “awareness” can be an eye-opener for many patients and there is good evidence that keeping a food journal can positively influence dietary patterns and even reduce “emotional” eating. But the idea that cognitively harnessing “will-power” to count calories (a very “unnatural” behaviour indeed), thereby creating and sustaining a long-term state of caloric deficit is rather optimistic at best. In fact, legions of people who have been… Read More »
Long-Term Health Outcomes After Bariatric Surgery
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… Read More »
Gastric Bypass Vs. Sleeve Gastrectomy For Severe Obesity
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… Read More »
Obesity Reimagined: 2018 JAMA Theme Issue On Obesity
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.” Also, “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. @DrSharma Edmonton, AB
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