Yesterday, I discussed the desperate need for scalable obesity treatments.
I pointed out that neither behavioural nor surgical interventions are readily scalable to provide long-term obesity treatments to the over 7,000,000 Canadians currently considered to have obesity.
I also noted that, like for other chronic diseases, only medical treatments with anti-obesity medications have the potential for scalability in the millions – we do this regularly for the millions of people living with diabetes, hypertension, heart disease, or any of the other common chronic diseases affecting Canadians.
Nevertheless, before we discuss what it would take to scale up medical treatments, let us take a look at whether all 7,000,000 affected Canadians really need obesity treatment.
Let us first note that the number 7,000,000 refers to Canadians with a BMI over 30. This may well overestimate the problem – as not everyone will actually need or likely benefit from anti-obesity treatments (BMI measures size – not health!).
In fact, if we apply the actual WHO definition of obesity, namely the presence of abnormal or excess body fat that impairs health, we can perhaps readily reduce this number by about 5-10% (anyone with Edmonton Obesity Stage 0) obesity, as these individuals are pretty healthy despite their excess weight. As there is no evidence that these rather healthy individuals would experience any long-term benefits from anti-obesity treatments, it would be entirely reasonable to take a “watch and wait” approach.
The 7,000,000 also includes an additional 15-20% of people, who would have rather mild impairments in health (Edmonton Obesity Stage 1), associated with a very low long-term risk – for these there is also no proven long-term benefit of obesity treatment.
Thus, we can readily exclude about 20 to 30% of individuals for whom the risk-benefit ratio (and thus, the cost-benefit relationship) would hardly justify the use of prescription medications.
This would reduce the number needed to treat by as many as 2 million – leaving us with about 5,000,000 left to treat.
Of these (by definition), all would have Edmonton Obesity Stage 2 or higher, meaning that they will all have some obesity related health impairments.
However, many of these individuals will have obesity related health risks (e.g. hypertension, diabetes, sleep apnea) that are currently well managed with other available treatments (e.g. anti-hypertensive or anti-diabetic medications, CPAP, etc.). For these well-managed patients, it is not clear what additional value anti-obesity medications would offer.
Let us assume that this number of well managed patients is about 50% of the remaining 5,000,000 – this leaves us with only 2,500,000 individuals with obesity related health problems that are not well managed with the available treatments for their comorbidities. It is probably only in these individuals that medical obesity treatment would make sense – both in terms of cost and benefit.
Let us further assume that for another 50% of the remaining for various reasons (e.g. too sick, too old, no ready access to medically supervised care, not interested in obesity treatment, etc.) medical treatment for obesity is not feasible.
This would leave us with only about 1,250,000 patients where medical treatment with prescription drugs would be both practical and likely cost-effective.
This is now a much more manageable problem. In fact, this is only about half the number of Canadians currently living with diabetes, a problem that is routinely managed with medical treatments.
So where are the anti-obesity treatments for these patients?
That will be the topic of tomorrow’s post.
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.
Unfortunately, all current treatments fail to “cure” obesity, as they fail to reset the set point to what would be considered “normal weight”. This makes ongoing treatment (be it behavioural, medical, or surgical) inevitable.
For all we know, any attempt at creating and sustaining weight loss regularly activates complex neurohormonal responses that serve to promote weight regain.
The only treatment, which may prove to be an exception is bariatric surgery (although this also only works as long as the surgery is in place – reverse the surgery, and the weight comes back).
Now, a paper by Hans Rudi Berthoud and colleagues, published in the International Journal of Obesity takes an in depth look at if and how gastric bypass surgery changes the body weight set point.
The paper reviews the data in support of the notion that surgery physiologically reprograms the body weight defense mechanism.
Thus, behavioural studies in animal models have shown that the defended body weight is indeed lowered after RYGB and sleeve gastrectomy.
For example, after surgeries, rodents return to their preferred lower body weight if over- or underfed for a period of time, and the ability to drastically increase food intake during the anabolic phase strongly argues against the physical restriction hypothesis.
Furthermore, these authors have also demonstrated that the defense of fat mass is less efficient (whereas defense of lean mass remains intact) after surgery.
However, as they point out,
“…the underlying mechanisms remain obscure. Although the mechanism involves central leptin and melanocortin signaling pathways, other peripheral signals such as gut hormones and their neural effector pathways likely contribute.”
Trying to elucidate the exact underlying mechanisms will hopefully not just improve our understanding of how bariatric surgery works, but also hopefully ultimately lead to the development of novel medical treatments that specifically target the body weight set point and its defence.
Given that untreated sleep apnea negatively affects restorative sleep, which in turn affects both metabolism and appetite, it may well be that sleep apnea is an important barrier to weight loss.
This is exactly what is suggested in a recent study by Whited and colleagues, published in Health Psychology.
The researchers conducted a secondary analysis of a 12 month randomized trial comparing 2 weight loss interventions consisting of dietary counseling for adults with obesity and metabolic syndrome.
Subjects who screened positive for high risk of sleep apnea using the STOP questionnaire (about 50% of the 175 participants), lost less weight (1.2% vs. 4.2%) and were less likely to lose 5% or greater (24% vs. 75%) than participants without risk for sleep apnea.
Thus, the authors conclude that,
“…an OSA screening indicating high risk identifies individuals who will struggle to lose weight when participating in a weight loss intervention, despite equal attendance at treatment sessions and study assessments. Findings of this study suggest that OSA is a significant barrier to weight loss.”
Whether or not treating sleep apnea makes weight loss any easier, the authors have this to offer:
“Although we found that participants reporting current OSA treatment had greater weight loss (6.5% vs. 0.6%), the small sample of individuals receiving OSA treatment (n = 24) precluded statistical comparison.”
“OSA screening as a standard component of weight loss interventions has a high potential for usefulness, as identified individuals can be targeted for more intense or comprehensive treatment. The benefits of OSA treatment as a standard part of weight loss interventions among individuals with obesity and metabolic syndrome has yet to be determined, and future research must include examination of adherence to both OSA and weight loss intervention components.”
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.