Why do doctors weigh people? Because, very early in medical school, we are taught that body weight is an important indicator of health.
While one may certainly argue about the value of a single weight measurement at any point in time (especially in adults), there is simply no denying that weight trajectories (changes in body weight – up or down) can provide important (often vital) clinical information.
Let’s begin with the easiest (and least arguable) situations of all – unintentional weight loss.
Among all clinical parameters one could possibly measure, perhaps non should be as alarming as someone losing weight without actively trying. In almost every single instance of “unintentional” weight loss, the underlying problem needs to be found, and more often than not, the diagnosis is probably serious (cancer is just one possibility).
As with any serious condition, the earlier you detect it, the sooner you can do something about it, therefore, the more often you weight someone, the more likely you will detect early “non-intentional” weight loss.
The contrary situation (un-intentional weight gain) is as important. When someone is gaining weight for no good reason, one needs to look for the underlying cause, which can include everything from an endocrine problem to heart failure.
On the other hand, weight stability, is generally a sign that things are probably “under control”, as they should be when energy homeostasis works fine and people are in energy balance.
Perhaps my own obsession with weighing people comes from my work in nephrology, where we obsess about people’s “dry weight” and use weight as a general means to monitor fluid status. The same is true for working with patients who have heart failure.
Note for all of the above, that while a single (random) weight measurement tells you very little (almost nothing) about anybody’s health status, unexplained changes in body weight are one of the most useful and important clinical signs in all of medicine. Obviously, to plot a trajectory, one has to start somewhere, which means that every patient needs to have a “baseline” body weight recorded somewhere in their chart. While this value may not provide any valuable information, the next one may.
This is why every single patient needs to be weighed at least once in a clinical setting.
As you will imagine, both the context and interpretation of serial weight measurements becomes most challenging in the setting of obesity management.
For one, there is no greater challenge than to suspect underlying “un-intentional” weight loss in someone who is actively trying to lose weight. When “suddenly” a weight loss strategy that was providing modest results “starts working” – all alarm bells should go off. Also, if weight loss is much better than “predicted” it is time to take a serious second look at what’s happening. Furthermore, you need to watch out for patients who are doing far better than expected (even after bariatric surgery) – it takes a keen clinical mind to watch out for weight loss that appears “too good to be true” (even if the patient is delighted to see the pounds drop off).
Also, in the obesity management setting, weight stability is an important clinical indicator. In someone at their maximum weight, it tells me that the patient is not actively gaining weight, which by definition means that the patient is in caloric balance – remember, the first sign of “success” in obesity management is when the patient stops gaining weight.
In someone, who has already lost weight (in the context of obesity management), weight stability means that the patient’s efforts are continuing (here weight stability is a means to monitor “control”) – weight regain means that the patient may have to re-engage in weight control efforts or (more often) that something has come up in that person’s life that is “sabotaging” their efforts and may need to be identified and addressed (e.g. lost a job, change in medication, depression, etc.). Again, the earlier you identify a “relapse”, the earlier you can intervene.
Finally, in someone attending an obesity clinic, who continues gaining weight, you can be sure that the underlying cause of weight gain has not yet been fully identified or addressed. In other words, the disease is not “controlled” and continues to “progress”.
Thus, patients must be aware, that asking not to be weighed (usually out of shame or embarrassment) derives their clinician of important and possibly “vital” information about their health status.
Again, while a single weight (or BMI) says very little about a patient’s health, changes in body weight (up or down) is a vital sign that should prompt further clinical investigation and possibly intervention.
None of this has anything to do with the fact that people can very well be healthy over a wide range of body shapes and sizes.
It also does not mean that we should take a “weight-centric” approach to obesity management – all of the usual HAES arguments remain valid, even when you regularly ask your patient to step on the scale.
Recording a weight trajectory should be no more “judgemental” than recording a fever chart in a patient with an infection – everything lies in the context and interpretation of the data.
Achieving and maintaining competencies is an ongoing challenge for all health professionals. But in an area like obesity, where most will have received rather rudimentary training (if any), most health professionals will likely be starting from scratch.
So what exactly must you expect of a health professional involved in the care of individuals living with obesity.
This is the subject of a white paper on “Provider Competencies for the Prevention and Management of Obesity“, developed with support from the Robert Wood Johnson Foundation.
The panel of authors led by Don Bradley (Duke) and William Dietz (George Washington) included representatives from over 20 national (US) professional organisations.
The competencies expected cover the following 10 topics:
Competencies for Core Obesity Knowledge
1.0 Demonstrate a working knowledge of obesity as a disease
2.0 Demonstrate a working knowledge of the epidemiology of the obesity epidemic
3.0 Describe the disparate burden of obesity and approaches to mitigate it
Competencies for Interprofessional Obesity Care
4.0 Describe the benefits of working interprofessionally to address obesity to achieve results that cannot be achieved by a single health professional
5.0 Apply the skills necessary for effective interprofessional collaboration and integration of clinical and community care for obesity
Competencies for Patient Interactions Related to Obesity
6.0 Use patient-centered communication when working with individuals with obesity and others
7.0 Employ strategies to minimize bias towards and discrimination against people with obesity, including weight, body habitus, and the causes of obesity
8.0 Implement a range of accommodations and safety measures specific to people with obesity
9.0 Utilize evidence-based care/services for people with obesity or at risk for obesity
10.0 Provide evidence-based care/services for people with obesity comorbidities
Some of the topics include further subtopics that are deemed especially relevant.
Thus, for e.g., topic 6.o, regarding communication, includes the following sub-competencies:
6.1 Discuss obesity in a non-judgmental manner using person-first language in all communications
6.2 Incorporate the environmental, social, emotional, and cultural context of obesity into conversations with people with obesity
6.3 Use person- and family-centered communication (e.g., using active listening, empathy, autonomy support/shared decision making) to engage the patient and others
Similarly, topic 7.0, regarding the issue of weight bias and discrimination, includes the following sub-competencies:
7.1 Describe the ways in which weight bias and stigma impact health and wellbeing
7.2 Recognize and mitigate personal biases
7.3 Recognize and mitigate the weight biases of others
This is clearly a forward-thinking outline of competencies that we will hopefully come to expect of most health professionals, given that virtually every health professional, no matter their specialty or scope of practice, will likely be called upon to care for people living with obesity.
The full document can be downloaded here.
Readers may by now be familiar with the GLP-1 analogue liraglutide, which has now been approved at the 3 mg dose (Saxenda(R)) for long-term obesity treatment in a growing number of countries.
Now, Novo Nordisk, the maker of liraglutide, announced preliminary results from their long-acting GLP-1 analogue semaglutide, suggesting a rather remarkable ~14% weight loss in a one-year double-blind placebo controlled dose-finding study.
According to the company’s press release,
In the trial, 957 people with obesity were randomised to treatment with doses of semaglutide between 0.05 to 0.4 mg/day or placebo. Liraglutide 3.0 mg/day was included for comparison. Approximately 100 people were included in each active treatment arm in combination with diet and exercise. All people in the trial were treated for 52 weeks followed by a 7-week follow-up period.
From a mean baseline weight of around 111 kg and a body mass index of approximately 39 kg/m2, a weight loss up to 17.8 kg was observed after 52 weeks of treatment with semaglutide. This corresponded to an estimated 13.8% weight loss compared to the weight loss of 2.3% achieved by diet, exercise and placebo alone, with all treatment arms adjusted for people discontinuing treatment in the study. The results from the liraglutide 3.0 mg treatment arm were broadly in line with previously reported data.
Side effects were mainly reported as gastro-intestinal, as expected from this class of hormone analogues.
Clearly, if borne out by the final publication and confirmed in larger and longer studies, semaglutide may well prove to be even more effective than liraglutide.
It may be worth noting, that the ~14% weight loss reported in this trial comes very close to the mean ~15% weight loss seen with adjustable gastric banding, a bariatric surgical technique that is now increasingly seen as obsolete due to long-term complications and loss of effectiveness.
I’m guessing it’s now on to Phase 3 for this promising anti-obesity drug.
Disclaimer: I have received speaking and consulting honoraria from Novo Nordisk, the maker of liraglutide and semaglutide
The final and eight item on the disease definition modification checklist developed by the Guidelines International Network (G-I-N) Preventing Overdiagnosis Working Group published in JAMA Internal Medicine, deals with issue of determining the benefit/harm ratio of the proposed new definition.
With terms to redefining obesity as the presence of abnormal or excess body fat that impairs health, I have discussed the potential benefits and harms in previous posts.
The question is, whether or not the overall balance comes down on the benefit or harm side of the equation.
Here, the authors of the checklist have the following to offer,
“Modifying a disease definition should be guided by a balanced assessment of the anticipated benefits and harms, using the best evidence available. The definition should reflect the values and preferences of patients and the wider community and include the impact on resource usage….In general, we recommend that panels consider both an individual and societal approach to assessing the overall benefits and harms of changing disease definitions. We recommend introducing a new disease definition where there is an expected positive balance of harms and benefit for individuals, and in aggregate at the societal level.”
In addition, the authors note,
“Different definitions may be required for research purposes, for example more stringent standardization, than for clinical purposes where more stringent definitions may deny access to care for patients who would benefit.”
Thus, as we have seen, changing disease definitions is not just a matter of opinion but rather, the pros and cons must be considered both at an individual and societal (resource) level.
That said, disease definitions are in constant flux as new knowledge and treatments emerge – obesity, should be no exception.
Indeed, guidelines would be amiss in not reconsidering the validity of current definitions and exploring potential changes as part of the guidelines process. The published checklist can certainly serve as a guide for this process.
The seventh item on the disease definition modification checklist developed by the Guidelines International Network (G-I-N) Preventing Overdiagnosis Working Group published in JAMA Internal Medicine, deals with issue of potential harms to patients.
Given the obvious benefits of redefining obesity as the presence of abnormal or excess body fat that impairs health outlined in the previous post, it is nevertheless prudent to explore the possibility of unintentional harms.
Obviously, expanding the term obesity to include millions of people, who currently fall under the BMI threshold but may well have health impairments attributable to their body fat, may not sit well with these folks. In fact, they may find themselves shocked to learn that they would now be considered to have obesity (more a reflection of the stigma attached to this term, than its non-judgemental medical meaning).
Thus, the authors of checklist remind us that,
“The potential harms from diagnosis include the physical harms of diagnosis and treatment; psychological effects, such as anxiety; social effects, such as stigma and discrimination; and financial consequences, such as effects on employment….Potential harms also include the misapplication and misinterpretation of the disease definition when taken from a confined research application to more widespread clinical use.”
A, perhaps more concerning issue, is the impact that redefining obesity may have on limited resources for obesity management in the healthcare system.
“Changes in resource usage can result in harm by reducing access to care for some patients and by diversion and distraction of clinical care. This can happen at both the societal level, with resources taken from areas more important to health, and at the individual level, by distracting individuals from activities more important to their well-being. Modifications of disease definitions can have considerable impacts on costs, including the costs of testing, and the resources needed for treatment and follow-up for those diagnosed using the new criteria. There may also be resources needed for training and implementation regarding the change, and to minimise misdiagnosis. Costs are particularly important in low- and middle-income countries where inappropriate disease definitions can result in considerable diversion of limited health care resources.”
These concerns are far from trivial. Not only are current resources for managing obesity in our healthcare systems limited (to non-existant), but one of the main reasons that employers and payers balk at providing access to obesity treatments, is the sheer number of individuals that already qualify for such treatments. Significantly expanding the pool of eligible patients, is therefore. unlikely to be met with much enthusiasm from these stakeholders.
Not only would one need to demonstrate that providing obesity treatments to people currently below the BMI threshold can significantly reduce their risks, one would also need to demonstrate that such efforts turn out to be cost-effective in the long-term.
Given our limited treatments, there does not appear any practical way of providing these treatments to everyone who meets the current BMI definition of obesity, let alone the millions of additional people, who would be considered to have obesity, if the disease definition was expanded to include anyone whose health may be impaired by the presence of abnormal or excess body fat.
Thus, as much as redefining obesity may make biological sense based on our understanding of the complex pathophysiology and substantial health impacts of this chronic disease, the societal harms (particularly on resources) of such a move must be carefully considered.