Cesari M, Fielding RA, Pahor M, et al.
J Frailty Aging 2012;1:102-10
Publication date: September 1, 2012
In this consensus document, the International Working Group on Sarcopenia discusses the current state of the art in the development of biomarkers to be used in clinical trials on sarcopenia. Sarcopenia was originally described as the age-related decrease in skeletal muscle mass, but until recently there was a lack of consensus on its operational definition. In the past two years, a number of academic societies have put forward operational definitions. Although each consensus definition has some distinct features, there is general agreement on the following characteritics: an objective measure of muscle or fat free mass using dual energy X-ray absorptiometry (DXA) or computed tomography (CT), a reliable measure of muscle strength, and/or an objective test of physical functioning. There are currently numerous parameters that are potentially able to track the age-related skeletal muscle decline.
The authors make the following recommendations:
1) Adoption of comprehensive operative definitions of sarcopenia
The lack of a unique operative definition of sarcopenia and the numerous methodological issues could potentially hinder efforts to study sarcopenia and to develop effective treatments. The current ambiguities can be easily overcome by adopting flexible and comprehensive approaches in the design of studies, for example by avoiding reliance on a single parameter or technique to evaluate age-related skeletal muscle decline.
2) MRI and CT scan to be equally considered as “gold standard” imaging techniques
It is now clear that to be adequately assessed, the sarcopenia phenomenon cannot merely rely on the evaluation of the contractile part of skeletal muscle. Therefore, techniques allowing the simultaneous evaluation of fat and muscle should be preferred. DXA, CT and MRI are the most important assessment instruments. CT and MRI should be considered the “gold standard” techniques.
3) Adequate length of study
To evaluate the efficacy of a specific intervention on sarcopenia, it is necessary that the follow-up will be sufficiently long to allow the hypothesized modifications of biomarkers. A 6-month period is generally considered as the minimum time frame to expect changes in imaging parameters.
The authors conclude that the study of sarcopenia as a “work in progress”, always amenable to changes and redirections. In this context, it is critical that an ongoing dialogue be initiated and sustained amongst investigators with an interest in age-dependent decline of muscle.