Shifting to ‘disagree to disagree’ using EBM

What would you consider a disease?

This question has been formulated in different ways in the previous two blogs The evidence of what?  and Trustworthy evidence or paid lip service. Evidence-based medicine (EBM) seems to lack explicit considerations of the properties of the phenomena that we want evidence about (1–4). The consequence can be a discrepancy between potentially correct evidence and our fundamental understanding of the phenomenon. Hypertension was used as an example: clear evidence of being a risk factor but unclear and unaware considerations of what constitutes a disease turns it into overdiagnosis (5).

Following example is chosen by its properties of being an existential condition: sarcopenia is the phenomenon of age-related loss of muscle mass and function and was assigned with an ICD-10-CM diagnosis code in 2016 (6).

For clarity, let us assume that the current evidence of sarcopenia is all highly trustworthy (6–9):

• The condition is caused by: age, lack of activity, genetic factors, and insufficient energy or protein intake due to e.g. anorexia or malabsorption.
• Can lead to: frailty, falls and fractures, cardiac and respiratory diseases, cognitive impairment, low quality of life, and death.
• Main treatment: resistance exercise, optionally supplemented with a high uptake of essential amino acids and vitamin D.
• Prevalence: potentially up to 2 billion people aged ≥60 years in 2050 worldwide.

Does the presented evidence show that sarcopenia should be diagnosed? Or does the evidence show natural life conditions and correlations that are related to getting older? Should we diagnose because it is a disease to loose muscle mass when you turn old? Or should we diagnose because it is a potential solvable problem for some?

In the case of hypertension, we are diagnosing a risk (a continuum) and evidence is insufficient to draw a line for the reach of the diagnosis. Regarding sarcopenia, evidence is insufficient to decide which existential phenomena that should be diagnosed. EBM is a crucial help for medical research and practice and EBM does avoid overdiagnosis, but it seems insufficient to suggest tools to discuss the properties of the diseases we are diagnosing including the limitations (1–4).

Without such discussions all kind of other factors and interests can dictate the development. In the case of sarcopenia, the evidence is used as the argument to consider the condition a diagnosis and disease (6–8). The evidence is used as if evidence speaks for itself, as if evidence-based health correlations naturally legitimise the creation of a new diagnosis. Such an approach opens for any condition to potentially become a disease as soon as evidence backs it up and can be used for conflicting interests. This challenges our fundamental idea and understanding of a disease.

EBM could promote explicit considerations from those who want to influence the diagnostic use by stating 1) what they consider a disease and why, 2) the reasons why the given condition should be considered a disease. The point of such an EBM-initiated discussion is not to agree but to point out that we disagree, that the real question may not be about evidence but underlying values and preferences.

1. Doust J, Vandvik PO, Qaseem A, Mustafa RA, Horvath AR, Frances A, et al. Guidance for modifying the definition of diseases: A checklist. JAMA Intern Med. 2017;177(7):1020–5.
2. Guyatt G, Rennie D, Meade M, Cook D. Users’ guides to the medical literature : a manual for evidence-based clinical practice [Internet]. 3rd ed. McGraw-Hill Education; 2015 [cited 2019 Mar 27]. 697 p. Available from: https://jamaevidence.mhmedical.com/content.aspx?bookid=847&sectionid=69030714
3. Heneghan C, Mahtani KR, Goldacre B, Godlee F, Macdonald H, Jarvies D. Evidence based medicine manifesto for better healthcare. BMJ [Internet]. 2017;357:15–7. Available from: http://dx.doi.org/doi:10.1136/bmj.j2973
4. Guyatt GH, Oxman AD, Vist GE, Kunz R, Falck-Ytter Y, Schünemann HJ. Rating Quality of Evidence and Strength of Recommendations: GRADE: What Is “Quality of Evidence” and Why Is It Important to Clinicians? Source BMJ Br Med J [Internet]. 2008;336(7651):995–8. Available from: http://www.jstor.org/stable/20509658%5Cnhttp://www.jstor.org/stable/20509658?seq=1&cid=pdf-reference#references_tab_contents%5Cnhttp://about.jstor.org/terms
5. Martin SA, Boucher M, Wright JM, Saini V. Mild hypertension in people at low risk. BMJ [Internet]. 2014 Sep 14 [cited 2019 Feb 5];349:g5432. Available from: https://www.bmj.com/content/349/bmj.g5432
6. Cruz-Jentoft AJ, Bahat G, Bauer J, Boirie Y, Bruyère O, Cederholm T, et al. Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing [Internet]. 2019 Jan 1 [cited 2019 Feb 6];48(1):16–31. Available from: https://academic.oup.com/ageing/article/48/1/16/5126243
7. Anker SD, Morley JE, von Haehling S. Welcome to the ICD-10 code for sarcopenia. J Cachexia Sarcopenia Muscle [Internet]. 2016 Dec [cited 2019 Feb 5];7(5):512–4. Available from: http://www.ncbi.nlm.nih.gov/pubmed/27891296
8. Cao L, Morley JE. Sarcopenia Is Recognized as an Independent Condition by an International Classification of Disease, Tenth Revision, Clinical Modification (ICD-10-CM) Code. J Am Med Dir Assoc [Internet]. 2016 Aug 1 [cited 2019 Feb 5];17(8):675–7. Available from: http://www.ncbi.nlm.nih.gov/pubmed/27470918
9. Cruz-Jentoft AJ, Pierre Baeyens J, Bauer JM, Boirie Y, Cederholm T, Landi F, et al. Sarcopenia: European consensus on definition and diagnosis Report of the European Working Group on Sarcopenia in Older People. Age Ageing [Internet]. 2010 [cited 2019 Feb 5];39:412–23. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2886201/pdf/afq034.pdf

Christoffer Bjerre Haase is Doug Altman Scholar and a researcher and medical doctor from University of Copenhagen. Based on the theory of science, philosophy and evidence-based medicine, Christoffer is primarily interested in the inter-relations between the concepts of overdiagnosis and diagnosis/disease and the ways (medical) science and societal discourses influence those concepts.

Christoffer Bjerre Haase has no conflict of interest