Readers will recall previous posts on the STAMPEDE trial, an ongoing trial of 150 patients who had type 2 diabetes and a BMI of 27 to 43 who were randomly assigned to receive intensive medical therapy alone or intensive medical therapy plus Roux-en-Y gastric bypass or sleeve gastrectomy.
Now the 5 year results of this trial have been published in the New England Journal of Medicine.
Of the 150 patients who underwent randomization, 1 patient in the medical-therapy group died during the 5-year follow-up period (from myocardial infarction during year 4) and 1 patient in the sleeve-gastrectomy group had a stroke; 134 of the remaining 149 patients (90%) completed 5 years of follow-up. One patient in the medical-therapy group, underwent gastric bypass during year 3, owing to failure of the medical treatment. One patient in the sleeve-gastrectomy group underwent gastric bypass during year 4 for the treatment of a gastric fistula.
At 5 years, the criterion for the primary end point (Hba1c <6% without the use of anti-diabetic mediations) was met by 2 of 38 patients (5%) who received medical therapy alone, as compared with 14 of 49 patients (29%) who underwent gastric bypass and 11 of 47 patients (23%) who underwent sleeve gastrectomy.
At 5 years, changes from baseline observed in the gastric-bypass and sleeve-gastrectomy groups were superior to the changes seen in the medical-therapy group with respect to body weight (−23%, −19%, and −5% in the gastric-bypass, sleeve-gastrectomy, and medical-therapy groups, respectively), triglyceride level (−40%, −29%, and −8%), high-density lipoprotein cholesterol level (32%, 30%, and 7%), use of insulin (−35%, −34%, and −13%), and quality-of-life measures.
Excessive weight gain was observed in 19% of the patients in the medical-therapy group and in no patients in either surgical group.
No major late surgical complications were reported except for the one reoperation mentioned above.
From these findings the author conclude that,
“…bariatric surgery was superior to intensive medical therapy in terms of glycemic control, weight reduction, medication reduction, improvement in lipid levels, and quality of life. Patients who underwent gastric bypass or sleeve gastrectomy were significantly more likely to achieve and maintain a glycated hemoglobin level of 6.0% or less, with or without medications, than were those who received intensive medical therapy alone…The surgically treated patients had superior glycemic control throughout the 5-year period while also using fewer diabetes medications, including insulin. More than 88% of the surgical patients had glycemic control that was considered to be very good to acceptable (average glycated hemoglobin level of 7.0%), without the use of insulin. A majority of the surgical patients who achieved a glycated hemoglobin level of 6.0% or less reached that target without the use of diabetes medications, whereas none of the patients in the medical-therapy group reached that target without the use of diabetes medications.”
No doubt this study supports the notion of long-term benefits of bariatric surgery (even in people with BMI in the 27-34 range) compared to intensive medical treatment alone. Clearly, this should be a treatment that may be considered for patients with type 2 diabetes, who struggle with glycemic control.
If you’re wondering why, the answer is rather simple.
According to a paper by Robert Kushner and colleagues published in the journal Teaching And Learning In Medicine, competencies in obesity prevention, assessment, and treatment are apparently not really required, at least not based on the questions that young doctors can expect to be asked in licensing exams.
The researchers examined the coverage and distribution of obesity-related items on the three step United States Medical Licensing Examination (USMLE), which every practicing US physician (irrespective of the specialty or discipline) has to pass to qualify for licensing.
Although the USMLE question panel did include over 80o multiple-choice items containing obesity-related keywords, 58% of these items were represented by only 4 of 17 organ systems, and 80% of coded items were represented by only 6 of the 107 American Board of Obesity Medicine subdomains.
While the majority of obesity-coded items pertained to the diagnosis and management of obesity-related comorbid conditions, they did not directly address the prevention, diagnosis, or management of obesity itself.
In medicine (as in any other discipline), students focus on topics that they can expect to encounter in their exams – clearly, diagnosing obesity and managing it, is not one of them.
Although “weight-loss” is a booming global multi-billion dollar business, we desperately lack effective long-term treatments for this chronic disease – the vast majority of people who fall prey to the natural supplement, diet, and fitness industry will on occasion manage to lose weight – but few will keep it off.
Thus, there is little evidence that the majority (or even just a significant proportion) of people trying to lose weight with help of the “commercial weight loss industry” will experience long-term health benefits.
When it comes to evidence-based treatments, there is ample evidence that behavioural interventions can help patients achieve and sustain important health benefits, but the magnitude of sustainable weight loss is modest (3-5% of initial weight at best).
Furthermore, although one may think that “behavioural” or “lifestyle” interventions are cost-effective, this is by no means the case. Successful behaviour change requires significant intervention by trained health professionals, a limited and expensive resource to which most patients will never have access. Moreover, there is ample evidence showing maintenance of long-term behaviour change requires significant on-going resources in terms of follow-up visits – thus adding to the cost.
This severely limits the scalability of behavioural treatments for obesity.
If for example, every Canadian with obesity (around 7,000,000) met with a registered dietitian just twice a year on an ongoing basis (which is probably far less than required to sustain ongoing behaviour change), the Canadian Health Care system would need to provide 14,000,000 dietitian consultations for obesity alone.
Given that there are currently fewer than 10,000 registered dietitians in Canada, each dietitian would need to do 14,000 consultations for obesity annually (~ 70 consultations per day) or look after approximately 7,000 clients living with obesity each year. Even if some of these consultations were not done by dietitians but by less-qualified health professionals, it is easy to see how this approach is simply not scalable to the size of the problem.
A similar calculation can be easily made for clinical psychologists or exercise physiologists.
Thus, behavioural interventions for obesity, delivered by trained and licensed healthcare professionals are simply not a scalable (or cost-effective) option.
At the other extreme, we now have considerable long-term data supporting the morbidity, mortality, and quality of life benefits of bariatric surgery. However, bariatric surgery is also not scalable to the magnitude of the problem
There are currently well over 1,500,000 Canadians living with obesity that is severe enough to warrant the costs and risks of surgery. However, at the current pace of 10,000 surgeries a year (a number that is unlikely to dramatically increase in the near future), it would take over 150 years to operate every Canadian with severe obesity alive today.
This is where we have to look at how Canada has made significant strides in managing the millions of Canadians living with other chronic diseases?
How are we managing the over 5,000,000 Canadians living with hypertension?
How are we managing the over 2.5 million Canadians living with diabetes?
How are we managing the over 1.5 million Canadians living with heart disease?
The answer to all is – with the help of prescription medications.
There are now millions of Canadians who benefit from their daily dose of blood pressure-, glucose-, and cholesterol-lowering medications. The lives saved by the use of these medications in Canada alone is in the 10s of thousands each year.
So, if millions of Canadians take medications for other chronic diseases (clearly a scalable approach), where are the medications for obesity?
Sadly, there are currently only two prescription medications available to Canadians (neither scalable, one due to cost the other due to unacceptable side effects).
So what would it take to find treatments for obesity that are scalable to the magnitude of the problem?
More on that in tomorrow’s post.
Yesterday, I posted on a study suggesting that people at high risk of obstructive sleep apnea may have a harder time losing weight that people without sleep apnea.
This prompted a reader to send me a link to a study by Luciano Drager and colleagues, published in Thorax, that presents a meta-analysis of randomised controlled trials on the effect of CPAP treatment on body weight.
The authors found 25 randomised controlled trials (RCTs) enrolling over 3000 patients with OSA ranging from 1 to 48 months in duration.
Paradoxically, they report that overall CPAP is associated with a 0.5 kg weight gain compared with control therapy.
Whether this weight gain is clinically relevant or not, the key finding is that (perhaps contrary to popular belief – including my own), the data does not support the idea that commencement of CPAP treatment for sleep apnea leads to weight loss.
As for the reasons for weight gain, an accompanying editorial by Sanjay Patel has this to offer,
“The reduction in leptin levels associated with CPAP therapy may result in increased hunger if the degree of leptin resistance does not change. Another explanation is that CPAP leads to reduced energy expenditure during sleep, as work of breathing is reduced due both to a patent upper airway as well as lung volumes rising to a more efficient point on the pressure–volume curve. Removal of the anorectic effects of hypoxia also may play an important role.”
It is also not exactly clear where the additional weight goes.
“A number of trials have demonstrated no substantial impact of CPAP on visceral fat volume, although the imaging methods used may not be sensitive enough to exclude the small magnitude of weight gain observed. Improvements in growth hormone and insulin-like growth factor 1 signalling with CPAP might result in increased muscle mass.13 Further studies are clearly needed to determine whether CPAP-induced weight gain represents increases in fat, lean body or water compartments.”
As for the potential health effects of the weight gain,
“The impact of 0.5 kg weight gain on health outcomes is fairly minimal and so should not change decision making regarding the use of CPAP in symptomatic OSA. However, it does give one pause regarding the use of CPAP in asymptomatic OSA where a cardiovascular benefit of CPAP has yet to be definitively established and makes more urgent the need for RCTs adequately powered to assess meaningful outcomes in this population.”
Clearly, the relationship between sleep apnea and body weight is a fair bit more complex than I would have thought.
Also, whether or not treating sleep apnea actually makes it easier for patients to lose weight (if they get adequate obesity treatment) remains to be seen.
Now, the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO), has published a new Position Statement on indications for surgery for obesity and weight-related diseases, published in Obesity Surgery.
Recommendations are graded based on the strength of the current evidence.
Recommendations with the highest strength of evidence include the following:
- Surgery for obesity and weight-related diseases is a codified discipline that has proven to be effective in the treatment of obesity resulting in long-term weight loss, improvement in or resolution of comorbidities, and the lengthening of life expectancy. (Level of evidence 1, grade of recommendation A)
- Surgery for obesity and weight-related diseases is a safe and effective therapeutic option for the management of T2DM in patients with obesity. Along with optimal medical treatment and lifestyle adjustment, it has been demon- strated that surgery for obesity and weight-related diseases can achieve a better glycemic control, lower glyco- sylated hemoglobin, and reduction of diabetes medications than optimal medical and lifestyle treatment alone. (Level of evidence 1, grade of recommendation A)
- Surgery for obesity and weight-related diseases demonstrated an excellent short- and midterm risk/benefit ratio in patients with class I obesity (BMI 30–35 kg/m2) suffering from T2DM and/or other comorbidities.
(Level of evidence 1, grade of recommendation A)
- Obesity, and visceral obesity in particular, is a major modifiable risk factor for cardiovascular diseases (CVD). Weight loss induced by surgery has been shown to reduce CVD risk, with the most relevant reductions in risk ob- served in the group of patients having the higher CVD risk before surgery. These patients obtain the most significant metabolic improvements thereafter. (Level of evidence 1, grade of recommendation A)
- Weight loss induced by surgery for obesity and weight- related diseases is associated to a reduction in the inci- dence of major cardiovascular events in patients with obesity, including myocardial infarction and stroke. Event reductions are more relevant in patients with a high cardiovascular risk before surgery. (Level of evidence 1, grade of recommendation A)
- Surgery for obesity and weight-related diseases may result in resolution/improvement of obstructive sleep apnea syndrome (OSAS). (Level of evidence 1, grade of recommendation A)
- In patients undergoing surgery for obesity and weight- related diseases, weight loss results in a substantial im- provement in pain and a reduction of disability derived from joint disease. (Level of evidence 1, grade of recommendation A)
- Surgery for obesity and weight-related diseases has proven to be effective in determining the overall improvement of the quality of life of patients suffering from obesity. (Level of evidence 1, grade of recommendation A)
- The improvement in the quality of life of the patient with obesity treated by surgery for obesity and weight-related diseases is independent from the type of performed procedure. (Level of evidence 1, grade of recommendation A)
- Surgery for obesity and weight-related diseases is effective in patients with class I obesity (BMI 30–35 kg/m2) and comorbidity. (Level of evidence 1, grade of recommendation A)
In addition, there are numerous recommendations, for which the evidence is perhaps less robust but nevertheless promising.
These recommendations cover a wide range of health issues including gastroesophageal reflux disease (GERD), hepatobiliary diseases, mental health, endocrinopathies and fertility, cancer and organ transplantation, pseudotumor cerebri, chronic inflammation, urinary tract and renal function, functional status, and quality of life.
I was particularly pleased to see the statement include recommendations regarding the limitations of BMI and an extensive discussion of the Edmonton Obesity Staging System as a potential guide to better defining indications for surgery.