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These organisations endorsed the findings in the final document. The group met and addressed the following questions, using the medical literature to build evidence-based answers: i What is sarcopenia? EWGSOP reviewed a wide range of tools that can be used to measure the specific variables of muscle mass, muscle strength and physical performance.
Our paper summarises currently available data defining sarcopenia cut-off points by age and gender; suggests an algorithm for sarcopenia case finding in older individuals based on measurements of gait speed, grip strength and muscle mass; and presents a list of suggested primary and secondary outcome domains for research. Once an operational definition of sarcopenia is adopted and included in the mainstream of comprehensive geriatric assessment, the next steps are to define the natural course of sarcopenia and to develop and define effective treatment.
A grave change associated with human ageing is progressive decline in skeletal muscle mass, a downward spiral that may lead to decreased strength and functionality. Sarcopenia has since been defined as the loss of skeletal muscle mass and strength that occurs with advancing age [ 3 ].
However, a widely accepted definition of sarcopenia suitable for use in research and clinical practice is still lacking. Geriatric syndromes are common, complex and costly states of impaired health in older individuals. Geriatric syndromes result from incompletely understood interactions of disease and age on multiple systems, producing a constellation of signs and symptoms. Delirium, falls and incontinence are examples of geriatric syndromes [ 4 ].
We suggest it may be likewise helpful to recognise sarcopenia as a geriatric syndrome because this view promotes its identification and treatment even when the exact causes remain unknown [ 5, 6 ]. What is the evidence that age-related sarcopenia fits the current definition of a geriatric syndrome?
Sarcopenia is prevalent in older populations [ 7, 8 ]. Sarcopenia has multiple contributing factors—the ageing process over the life course, early life developmental influences, less-than-optimal diet, bed rest or sedentary lifestyle, chronic diseases and certain drug treatments [ 9—11 ].
Sarcopenia represents an impaired state of health with a high personal toll—mobility disorders, increased risk of falls and fractures, impaired ability to perform activities of daily living, disabilities, loss of independence and increased risk of death [ 12—16 ].
While age-related sarcopenia is common and has huge personal and financial costs, sarcopenia still has no broadly accepted clinical definition, consensus diagnostic criteria, International Classification of Diseases 9th Revision ICD-9 codes or treatment guidelines.
To address these shortfalls, the European Union Geriatric Medicine Society EUGMS decided in to create a Sarcopenia Working Group that would develop operational definitions and diagnostic criteria for sarcopenia to be used in clinical practice as well as in research studies.
Literature reviews and discussions were guided by the following questions:. What variables will measure them, and what measurement tools and cut-off points will be used? Sarcopenia is a syndrome characterised by progressive and generalised loss of skeletal muscle mass and strength with a risk of adverse outcomes such as physical disability, poor quality of life and death [ 17, 18 ]. The EWGSOP recommends using the presence of both low muscle mass and low muscle function strength or performance for the diagnosis of sarcopenia.
Thus, diagnosis requires documentation of criterion 1 plus documentation of either criterion 2 or criterion 3 Table 1. The rationale for use of two criteria is: muscle strength does not depend solely on muscle mass, and the relationship between strength and mass is not linear [ 18, 19 ]. Thus, defining sarcopenia only in terms of muscle mass is too narrow and may be of limited clinical value. Some have argued that the term dynapenia is better suited to describe age-associated loss of muscle strength and function [ 20 ].
However, sarcopenia is already a widely recognised term, so replacing it might lead to further confusion. There are several mechanisms that may be involved in the onset and progression of sarcopenia Figure 1. These mechanisms involve, among others, protein synthesis, proteolysis, neuromuscular integrity and muscle fat content.
In an individual with sarcopenia, several mechanisms may be involved, and relative contributions may vary over time. Recognising these mechanisms and their underlying causes is expected to facilitate design of intervention trials that target one or more underlying mechanisms. Sarcopenia is a condition with many causes and varying outcomes.
While sarcopenia is mainly observed in older people, it can also develop in younger adults, as is likewise the case for dementia and osteoporosis. In some individuals, a clear and single cause of sarcopenia can be identified. In other cases, no evident cause can be isolated. Thus, the categories of primary sarcopenia and secondary sarcopenia may be useful in clinical practice.
In many older people, the aetiology of sarcopenia is multi-factorial so that it may not be possible to characterise each individual as having a primary or secondary condition. This situation is consistent with recognising sarcopenia as a multi-faceted geriatric syndrome. Sarcopenia staging, which reflects the severity of the condition, is a concept that can help guide clinical management of the condition.
This stage can only be identified by techniques that measure muscle mass accurately and in reference to standard populations. Recognising stages of sarcopenia may help in selecting treatments and setting appropriate recovery goals.
Staging may also support design of research studies that focus on a particular stage or on stage changes over time. Sarcopenia is featured in other syndromes associated with prominent muscle wasting.
The main reason to differentiate between them is to encourage research into age-related mechanisms of sarcopenia and to guide targeted and appropriate therapy for each. Cachexia has recently been defined as a complex metabolic syndrome associated with underlying illness and characterised by loss of muscle with or without loss of fat mass [ 22 ].
Cachexia is frequently associated with inflammation, insulin resistance, anorexia and increased breakdown of muscle proteins [ 23, 24 ]. Thus, most cachectic individuals are also sarcopenic, but most sarcopenic individuals are not considered cachectic.
Sarcopenia is one of the elements of the proposed definition for cachexia [ 22 ]. Very recently, a consensus paper expanding this definition of cachexia and identifying relevant issues on how to differentiate cachexia and sarcopenia was published by ESPEN, one of the EWGSOP-endorsing societies [ 25 ].
Frailty is a geriatric syndrome resulting from age-related cumulative declines across multiple physiologic systems, with impaired homeostatic reserve and a reduced capacity of the organism to withstand stress, thus increasing vulnerability to adverse health outcomes including falls, hospitalisation, institutionalisation and mortality [ 26, 27 ].
Fried et al. Frailty and sarcopenia overlap; most frail older people exhibit sarcopenia, and some older people with sarcopenia are also frail. The general concept of frailty, however, goes beyond physical factors to encompass psychological and social dimensions as well, including cognitive status, social support and other environmental factors [ 26 ]. In conditions such as malignancy, rheumatoid arthritis and ageing, lean body mass is lost while fat mass may be preserved or even increased [ 28 ].
This state is called sarcopenic obesity, and thus the relationship between age-related reduction of muscle mass and strength is often independent of body mass. It had long been thought that age-related loss of weight, along with loss of muscle mass, was largely responsible for muscle weakness in older people [ 29 ]. However, it is now clear that changes in muscle composition are also important, e. While weight changes vary widely between individuals, certain patterns of age-related change in body composition have been observed.
In ageing men, the percentage of fat mass increases initially, then levels off or decreases. Such change has been attributed to an accelerated decrease in lean mass, along with an initial increase and a later decrease in fat mass [ 31 ]. Women show a generally similar pattern [ 31 ]. Intramuscular and visceral fat increase with ageing while subcutaneous fat declines [ 18, 32, 33 ].
The parameters of sarcopenia are the amount of muscle and its function. The measurable variables are mass, strength and physical performance. The challenge is to determine how best to measure them accurately.
It is also important to recognise change by repeating the same measures over time in the same individuals. The following sections briefly review measurement techniques that can be used and discuss their suitability for research and clinical practice settings.
A wide range of techniques can be used to assess muscle mass [ 34 ]. Cost, availability and ease of use can determine whether the techniques are better suited to clinical practice or are more useful for research.
Measurements of muscle mass, strength, and function in research and practice a. Body imaging techniques. Three imaging techniques have been used for estimating muscle mass or lean body mass—computed tomography CT scan , magnetic resonance imaging MRI and dual energy X-ray absorptiometry DXA.
CT and MRI are considered to be very precise imaging systems that can separate fat from other soft tissues of the body, making these methods gold standards for estimating muscle mass in research. High cost, limited access to equipment at some sites and concerns about radiation exposure limit the use of these whole-body imaging methods for routine clinical practice [ 8 ]. DXA is an attractive alternative method both for research and for clinical use to distinguish fat, bone mineral and lean tissues.
This whole-body scan exposes the patient to minimal radiation. The main drawback is that the equipment is not portable, which may preclude its use in large-scale epidemiological studies [ 8 ].
DXA is the preferred alternative method for research and clinical use. Bioimpedance analysis. Bioimpedance analysis BIA estimates the volume of fat and lean body mass. The test itself is inexpensive, easy to use, readily reproducible and appropriate for both ambulatory and bedridden patients.
Prediction equations have been validated for multiethnic adults [ 36 ] and reference values established for adult white men and women, including older subjects [ 37—39 ]. Total or partial body potassium per fat-free soft tissue. More recently, partial body potassium PBK of the arm has been proposed as a simpler alternative [ 40 ]. PBK of the arm is safe and inexpensive.
Anthropometric measures. Calculations based on mid-upper arm circumference and skin fold thickness have been used to estimate muscle mass in ambulatory settings. However, age-related changes in fat deposits and loss of skin elasticity contribute to errors of estimation in older people. There are relatively few studies validating anthropometric measures in older and obese people; these and other confounders make anthropometric measures vulnerable to error and questionable for individual use [ 14 ].
There are fewer well-validated techniques to measure muscle strength. Although lower limbs are more relevant than upper limbs for gait and physical function, handgrip strength has been widely used and is well correlated with most relevant outcomes. Again, cost, availability and ease of use can determine whether the techniques are better suited to clinical practice or are useful for research Table 4. It must be remembered that factors unrelated to muscle, e. Handgrip strength. Isometric hand grip strength is strongly related with lower extremity muscle power, knee extension torque and calf cross-sectional muscle area [ 13 ].
Low handgrip strength is a clinical marker of poor mobility and a better predictor of clinical outcomes than low muscle mass [ 13 ]. In practice, there is also a linear relationship between baseline handgrip strength and incident disability for activities of daily living ADL [ 42 ]. Muscle strength measures of different body compartments are correlated, so when feasible, grip strength measured in standard conditions with a well-studied model of a handheld dynamometer with reference populations can be a reliable surrogate for more complicated measures of muscle strength in the lower arms or legs.
Strength is about the magnitude of force generation, whereas power is about work rate work done per unit time.
Sarcopenia: European consensus on definition and diagnosis
Sarcopenia is a condition characterized by loss of skeletal muscle mass and function. Although it is primarily a disease of the elderly, its development may be associated with conditions that are not exclusively seen in older persons. Sarcopenia is a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength and it is strictly correlated with physical disability, poor quality of life and death. Risk factors for sarcopenia include age, gender and level of physical activity. In conditions such as malignancy, rheumatoid arthritis and aging, lean body mass is lost while fat mass may be preserved or even increased. The loss in muscle mass may be associated with increased body fat so that despite normal weight there is marked weakness, this is a condition called sarcopenic obesity. There is an important correlation between inactivity and losses of muscle mass and strength, this suggests that physical activity should be a protective factor for the prevention but also the management of sarcopenia.
These organisations endorsed the findings in the final document. The group met and addressed the following questions, using the medical literature to build evidence-based answers: i What is sarcopenia? EWGSOP reviewed a wide range of tools that can be used to measure the specific variables of muscle mass, muscle strength and physical performance. Our paper summarises currently available data defining sarcopenia cut-off points by age and gender; suggests an algorithm for sarcopenia case finding in older individuals based on measurements of gait speed, grip strength and muscle mass; and presents a list of suggested primary and secondary outcome domains for research. Once an operational definition of sarcopenia is adopted and included in the mainstream of comprehensive geriatric assessment, the next steps are to define the natural course of sarcopenia and to develop and define effective treatment. A grave change associated with human ageing is progressive decline in skeletal muscle mass, a downward spiral that may lead to decreased strength and functionality. Sarcopenia has since been defined as the loss of skeletal muscle mass and strength that occurs with advancing age [ 3 ].
El valor predictivo de la definición de sarcopenia del EWGSOP: resultados del estudio InCHIANTI
It is characterized by the degenerative loss of skeletal muscle mass, quality, and strength. The rate of muscle loss is dependent on exercise level, co-morbidities, nutrition and other factors. The muscle loss is related to changes in muscle synthesis signalling pathways. It is distinct from cachexia , in which muscle is degraded through cytokine- mediated degradation, although both conditions may co-exist. Sarcopenia is considered a component of frailty syndrome.