Asan Medical Centre, Seoul

Yesterday morning, I had the pleasure of presenting the Plenary Key Note Lecture at the 31st Annual Scientific Conference of the Korean Society for the Study of Obesity (KSSO).

The session was chaired by Professors Kwang-Won Kim (President) and Hye-Soon Park (Chair, Board of Directors) of KSSO at the most impressive Asan Medical Centre, a sprawling ~2500-bed hospital complex, one of the largest and most modern of Korean academic hospitals. The hospital is named after Asan, Chung Ju-Yung, the founder of Hyundai and the Asan Foundation.

While my talk focused on an etiological approach to obesity management (soon to be published in Obesity Reviews), I also spoke about the Edmonton Obesity Staging System (EOSS) and our early experience with this system in clinical practice. My Korean colleagues found this system most interesting and timely, as the issue of which obese people to prioritize for treatment is as relevant in Korea as it is in Canada.

While Korea, as do other Asian countries, defines obesity as a BMI greater than 25, this should not pose a barrier to applying EOSS to their population. Indeed, the advantage of EOSS is that it characterizes the degree of obesity not simply by size but rather based on the clinical assessment of mental and physical comorbidities.

I am most grateful to my Korean colleagues for the invitation and their incredibile hospitality and very much look forward to hearing about how they plan to adopt EOSS for Koreans.

AMS
Edmonton, Alberta

Yesterday, I blogged about the proposed Edmonton Obesity Staging System. This prompted a number of comments and questions.

Here a few quick answers regarding the Staging System:

1) The terms mild, moderate, and severe are of course subjective. In some cases there are objective measures (e.g. valid scales) to assess the severity of symptoms but in other cases, this call is really to be made by the medical professional based on the interview, physical exam and other assessments.

Although there may be some variability in judgement between clinicians, hopefully, the inter-rater reliability will not be too far off.

2) What is the definition of obesity related comorbidity?

Unfortunately, excess weight can lead to a wide range of health problems. However, it is often not entirely clear whether or not a specific problem in a given patient is really entirely weight related.

Thus for e.g. although obesity is a common cause of fatty liver disease, there are many other factors that can lead to excess accumulation of liver fat. Often it may only be possible to tell if a problem is obesity related when the problem actually gets better or even disappears with weight loss.

I generally suggest that in order to be considered obesity related, a problem has to meet at least two of the following three criteria.

1) There is good epidemiological evidence that the condition is more common in people with overweight or obesity.

2) There is evidence that the condition actually gets worse with weight gain and/or better with weight loss.

3) There is a plausible biological link between the condition and excess weight.

It the condition meets at least two of these criteria, it may be fair to assume that it is likely weight-related unless there is substantial reason to suspect another cause.

Once again, the final proof that a specific condition is in fact weight-related can only come from the demonstration that the condition actually does get better with weight loss (This of course does not apply to conditions like obesity related cancers, which, once established are unlikely to disappear or get better with weight loss).

Hopefully, these explanations provide some clarification. Several research projects are currently underway to further validate this staging system to increase its utility in medical research and practice.

Once again, all ideas and comments are greatly appreciated.

AMS
Edmonton, Alberta

Readers of these pages will recall that earlier this year Robert Kushner and I published a proposal for a new clinical obesity staging system in the International Journal of Obesity.

Rather than BMI (a measure of weight), the Edmonton Obesity Staging System (EOSS) ranks severity of obesity based on clinical assessment of weight-related health problems, mental health and quality of life. We proposed that this system would provide a far better guide to clinical decision making than using BMI class alone.

As we have now implemented the use of this system in our clinic and in the referral requirements to our program, we have also developed a simple chart and pocket tool that can be used as a reminder in a clinical setting.

Click here for Edmonton Obesity Staging System Chart

Click here for Edmonton Obesity Staging System Pocket Card

All comments are greatly appreciated.

AMS
Edmonton, Alberta

While I am taking a brief break from clinics and other obligations (including daily blog posts), I will be reposting past articles, which I still believe to be relevant but may have escaped the attention of the 100s of new readers who have signed up in the past months.

The following was first posted on 08/19/08

Many readers of this blog are familiar with the ongoing (endless?) discussion about whether or not obesity is a risk factor, a disease, a condition, or simply an extreme of the normal “bell curve” of body weights. Today, I want to throw in another term into this discussion. In fact, the more I think about it, the more I am convinced that we should look at obesity as a clinical sign - not unlike edema.

In the same manner that edema reflects the excess accumulation of fluid, obesity reflects the excess accumulation of body fat. As edema is a clinical sign of a perturbation of fluid homeostasis, excess fat accumulation is indicative of a perturbation in energy balance.

In a patient with edema, we can of course opt to simply provide symptomatic treatment by restricting salt and water intake, but my guess is that most experienced clinicians will likely make an effort to understand whether the fluid retention is a result of abnormal cardiac function, renal failure, venous or lymphatic stasis, vasodilatory drugs or a list of other possible causes of fluid retention.

Similarly, in a patient with excess body fat, we can simply prescribe “symptomatic treatment” by restricting food intake or increasing activity, or we can make an effort to truly understand the factors that are causing the patient to overeat or “undermove” (apologies for coining this term, but I kind of think it conveys the point). Obviously, whether or not the overeating is a result of peer pressure, hunger (meal skipping), depression, binge-eating, olanzapine, sugar-addiction, MC-4 receptor defect, or a craniopharyngeoma may well influence the choice of treatments.

Similarly, whether or not the “undermoving” results from lack of time, unsafe neighbourhoods, obstructive sleep apnea, anxiety disorders, depression, back pain, fibromyalgia, plantar fasciitis, vital exhaustion or quadroplegia will (hopefully) help determine the most appropriate and effective management strategy.

The idea that all people with excess body fat should simply eat less and move more is not unlike the notion that all people with edema should simply restrict their fluid intake and cut the salt.

If obesity is simply a “sign”, then “overeating” and “undermoving” are just symptoms!

The differential diagnosis of overeating and undermoving is complex and can involve sociocultural, psychological, medical and iatrogenic causes.

Let’s get more sophisticated in our diagnostics - hopefully our ability to address the underlying causes will follow.

AMS
Edmonton, Alberta

While I am taking a brief break from clinics and other obligations (including daily blog posts), I will be reposting past articles, which I still believe to be relevant but may have escaped the attention of the 100s of new readers who have signed up in the past months.

The following was first posted on 30/03/08 (the Edmonton Obesity Staging System suggested in this original post, is now published in the International Journal of Obesity. Also note the foresight expressed in this post in light of Margaret Wente’s thought-provoking comment published in yesterday’s Globe and Mail - as this “classic” blog post demonstrates, we were well over a year ahead of Margaret in our thinking about what constitutes obesity and who needs treatment - good to see the mainstream media catch up!).

Current definitions of obesity based on BMI and waist circumference (WC), while widely accepted, are hardly helpful in counseling individual patients. Readers of my blog are probably quite familiar with my views on this.

As most clinicians will readily agree, when dealing with indiviual patients, both measures lack sensitivity and specificity with regard to identifying the presence or risk of obesity-related risk factors, comorbidities, psychopathology, global functioning or quality of life.

In fact recent epidemiological studies emphasize that good health including low morbidity and mortality is possible over a wide range of BMI. Thus, basing the decision on who to treat and who to leave well alone solely on measures of weight or size is neither sensible nor does justice to the complexity of the relationship between excess body fat and its impact on health and well-being. The well-established obesity-chronic disease paradox makes decisions on who to treat and who not to treat even more uncertain.

Telling healthy large people who have no apparent comorbidities, functional limitations or reduced well-being to lose weight may be counterproductive in that it can introduce and reinforce dissatisfaction with body image, foster frustrations and despair (given the poor long-term success of weight loss attempts) and lead to unhealthy behaviours focusing on weight loss (e.g. excessive exercise or dieting) rather than on healthy lifestyles (which are possible at almost any weight).

Thus, for practical purposes, it is important to move beyond defining who needs obesity treatment simply based on BMI and/or WC to a more clinically meaningful system.

Indeed, what we direly need is a classification of obesity that is clinically relevant in that it helps identify patients who have or are at high-risk of obesity-related complications and are most likely to benefit from treatment.

In this context, it may be worthwhile to look at the systems of classification and staging used for other disease states.

Oncologists have long used the TNM system to classify the extent of cancer spread. This system has established itself for the classification and staging of the vast majority of cancers not only because it is clinically meaningful in that it reflects extent of disease, indicates prognosis and allows evaluation of treatment response but also facilitates surveillance and research.

Psychiatrists and other mental health workers now routinely report on their patients using the five axes set out in the DSM-IV, each of which refers to a different domain of information that help the clinician plan treatment and predict outcome. The five axes are:

Axis I Clinical Disorders (all mental disorders except Personality Disorders and Mental Retardation)

Axis II Personality Disorders and Mental Retardation

Axis III General Medical Conditions (must be connected to a Mental Disorder)

Axis IV Psychosocial and Environmental Problems (for example limited social support network)

Axis V Global Assessment of Functioning (Psychological, social and job-related functions are evaluated on a continuum between mental health and extreme mental disorder)

While these systems are by no means simple or easy for the layman to understand, they are clinically useful and provide a standardized framework within which it is possible to describe the extent and impact of disease in a way that all clinicians, researchers and payors will understand.

Contrast these systems to the rather simplistic obesity classification, where knowing that a given person has Class II obesity (BMI 35-39.9) tells you virtually nothing about that person’s health or well being. Furthermore, it provides no meaningful guide in determining outcomes: e.g. someone who weighs 120 Kg with a BMI of 39 (Class 2 obesity) despite losing 10 Kg (8% weight loss) still has Class II obesity (BMI 36). This classification neither tells us what (if any) comorbities were actually present or whether (or not) these actually got better.

Now I am no expert on disease classification and realise the large amount of work and consensus meetings that go into developing these classification systems. But I am a clinician, who regularly sees patients and would be happy to see even the simplest form of staging that provides a meaningful framework.

The simplest classification I can think of would be to use a staging system similar to the following:

Stage 0: no apparent obesity-related risk factors (blood pressure, lipids, glucose, etc.), physical symptoms, psychopathology, functional limitations, or impairment of well-being

Stage 1: presence of obesity-related sub-clinical risk factors (elevated blood pressure, impaired fasting glucose, fatty liver, etc.), mild physical symptoms (dyspnea on moderate exertion, occasional aches and pains, etc.), mild psychopathology, mild functional limitations or mild impairment of well-being

Stage 2: presence of established obesity-related chronic disease like hypertension, type 2 diabetes, sleep apnea, osteoarthritis, reflux disease, polycystic ovary syndrome, depression, anxiety disorder, moderate limitations in activities of daily living and/or well being.

Stage 3: established end-organ damage like myocardial infarction, diabetic complications, severe osteoarthritis, significant psychopathology, significant functional limitations and impairment of well-being

Stage 4: severe (end-stage?) disabilities from obesity-related chronic disease, severe disabling psychopathology, severe functional limitations and severe impairment of well-being

Thus for e.g. a 24 year-old physically active female with a BMI of 32 with no measurable risk factors, functional limitations or self-esteem issues would have Class I, Stage 0 Obesity - benefits of treatment will be marginal or non-existent.

A 32 year-old male with BMI of 36 with hypertension and sleep apnea would have Class III, Stage 2 Obesity - definite indication for obesity treatment.

A 45 year-old female with BMI of 54 who is in a wheel chair because of severe gonarthritis with severe hypoventilaltion would have Class III, Stage 4 Obesity - will require aggressive obesity treatment unless deemed palliative.

But this may not be the only conceivable system. In fact, given the significant importance of psychopathology, personality traits, physical disease, psychosocial and enviromental factors as well as global functioning, I wonder if an approach similar to the axes in DSM-IV may be best. Of course, one could easily envision combinations of both systems, e.g. applying staging to Axis III disorders.

Obviously any such system would need careful definitions and perhaps a complex manual of diagnostics and classifications similar to DSM-IV - but at least we would have a way to assess, describe, treat, monitor and research obesity in a way that goes beyond the relatively meaningless anthropometry-based classification, which is nothing short of useless in clinical practice.

I can see why health authorities, professional organisations and even clinicians may be reluctant to devise a more complex classification of obesity - all I can say is that the present classification does not provide a meaningful framework in which to make clinical decisions or evaluate outcomes. There is certainly a need for a more complex system to guide practice (and research).

More often than not in clinical medicine - simple is simply wrong!

AMS
Edmonton, Alberta