Dorit Tidhar; Jane M. Armer; Bob R. Stewart. Rehabilitation Oncology 2018;36:13–27

Main findings

This very interesting paper evaluates the objective outcome measures we use to determine minimal clinically important difference (MCID).

The outcomes evaluated were volume, symptoms, skin changes, infection rate, quality of life, strength/ endurance/ fitness/ functional disability.

The paper concludes:

• Lymphoedema is a chronic condition that requires life-long management. Investing in interventions that will lead to meaningful changes is of great importance to people who live with lymphoedema. As clinicians, deciding whether to change our practices, adopt new devices or techniques, invest in education, and refer to new therapies, we need to have more information than statistical significance alone.
• We need to know whether our patients will be happier, or healthier, with the available intervention. Will the change that they gain from the treatment make a difference for them? Furthermore, there is a need to correlate results to health care systems demands and find MCIDs that represent cost-effectiveness in the field of lymphedema management.
• The lymphedema population that is most researched is that of breast cancer survivors. Clinicians tend to generalize decision to their own patients based on the results of breast cancer studies. Lower-limb lymphedema, head and neck lymphedema, primary lymphedema, and other types will respond differently to an intervention than BCRL will do, and the expectations for success will be different as well. Therefore, further research is needed on different populations of patients with lymphedema and on different tools.
• Ideally, researchers should report on the expected outcome and on their definition of MCID using anchor as well as distribution-based methods. In this way, researchers and clinicians will be able to understand and explore the findings and transfer this new knowledge to practice.
• Anchor based methods include QOL, function, symptoms, general health, and more. Distribution based methods look at standard error of measurement and effect size.
• It is important to note MCID of a specific variable can be defined differently for/by the patient, the clinician, and the health care system. For example, with volume as an outcome, the clinician will aim for “maximum” reduction until stabilization to order a garment; the patient will want “just enough” so that he can bend his knee, climbstairs, etc; and the health care system will aim for “just enough” to reduce costs of hospitalization due to infection. The MCID “maximum” and “just enough” will be at different cut off points for the same variable. Similarly, the clinician may desire the referral threshold to be mild lymphedema to maximize outcomes with minimal treatments; the patient may desire relief from distressing symptoms, impaired function, or risk for recurrent infection, with a subjective definition for the threshold; and the health care system will desire later referral based on a higher limb volume difference to avoid unnecessary treatment in the event of transient or self-resolving swelling.
• Clinicians, as part of the health system, should be aware of the different interpretations of MCID that represent diverse expectations. Use and discussion of MCID in published articles should improve our understanding of what is clinically effective, thus leading to better use of resources and improved care for our patients with lymphedema.