What are the diagnostic criteria for sarcopenia?

Affecting millions of older adults globally, sarcopenia is a progressive muscle disease that involves the loss of skeletal muscle mass and function. Understanding what are the diagnostic criteria for sarcopenia is crucial for early detection, which can significantly improve health outcomes and quality of life for seniors.

Quick Summary

Diagnostic criteria for sarcopenia typically involve a multi-step process beginning with case-finding via questionnaires, followed by assessing muscle strength and quantity, and potentially physical performance, based on international consensus guidelines like EWGSOP2 and AWGS 2019.

Key Points

• Multi-step Approach: Diagnosing sarcopenia follows a sequence, from screening at-risk individuals to confirming the diagnosis with objective measures [1, 2, 3].

• EWGSOP2 (2018) Focuses on Strength: The European criteria prioritize low muscle strength (grip strength or chair stand) as the initial indicator, confirming with low muscle mass and classifying severity with poor physical performance [1].

• AWGS 2019 Offers Regional Guidelines: The Asian criteria provide population-specific cut-offs and a structured pathway, including an initial screening stage for primary care settings [2].

• Three Pillars of Diagnosis: All major criteria rely on assessing three key components: muscle strength, muscle quantity or quality, and physical performance [1, 2, 3].

• Measurements Vary by Criteria: While tests like handgrip strength, DXA for muscle mass, and gait speed are common, the specific cut-off points used to define 'low' vary between the EWGSOP2, AWGS 2019, and FNIH guidelines [1, 2, 3].

Sarcopenia: A Multi-faceted Diagnosis

The diagnosis of sarcopenia relies on a multi-step process involving assessing muscle strength, muscle quantity/quality, and physical performance [1, 2, 3]. International working groups like the European Working Group on Sarcopenia in Older People (EWGSOP2) and the Asian Working Group for Sarcopenia (AWGS 2019) provide evidence-based guidelines and cut-off points to standardize diagnosis [1, 2]. These frameworks typically involve screening to identify individuals at risk, followed by more objective measurements to confirm the diagnosis and classify severity [1, 2].

Leading Diagnostic Criteria Frameworks

Several prominent frameworks guide the diagnosis of sarcopenia, each with its own specific approach and cut-off points. The most widely referenced include the EWGSOP2, AWGS 2019, and the FNIH Sarcopenia Project criteria [1, 2, 3].

EWGSOP2 Diagnostic Criteria (2018) [1]

The EWGSOP2 framework starts with screening using tools like the SARC-F questionnaire. Probable sarcopenia is indicated by low muscle strength, assessed by handgrip strength (<27 kg for men, <16 kg for women) or the chair stand test (>15 seconds). Confirmed sarcopenia requires both low muscle strength and low muscle quantity/quality, often measured by DXA (ASM/h2 <7.0 kg/m2 for men, <6.0 kg/m2 for women) or BIA. Severe sarcopenia is diagnosed when low muscle strength, low muscle mass, and poor physical performance (e.g., gait speed ≤0.8 m/s, SPPB ≤8) are all present.

AWGS 2019 Diagnostic Criteria [2]

Designed for Asian populations, the AWGS 2019 criteria also employ a staged approach. Screening in community settings can use SARC-F, SARC-CalF, or calf circumference (<34 cm in men, <33 cm in women). Low muscle strength is assessed by handgrip strength (<28 kg for men, <18 kg for women) or low physical performance (gait speed <1.0 m/s or 5-time sit-to-stand ≥12 seconds). Confirmed sarcopenia requires low muscle mass (ASM/h2 via BIA ≤7.0 kg/m2 for men, ≤5.7 kg/m2 for women) in addition to either low strength or low performance. Severe sarcopenia involves low muscle mass, strength, and performance.

FNIH Sarcopenia Project Criteria (2014) [3]

The FNIH criteria use a data-driven approach, correlating diagnostic thresholds with adverse outcomes like mobility impairment. They define low muscle strength as grip strength <26 kg for men and <16 kg for women. Low muscle mass is defined by a low ratio of appendicular lean mass to BMI (ALM/BMI <0.789 for men, <0.512 for women). Mobility impairment (gait speed <0.8 m/s) is used to confirm weakness and link sarcopenia to functional limitations.

Comparison of Diagnostic Criteria

Feature	EWGSOP2 (2018) [1]	AWGS 2019 [2]	FNIH Sarcopenia Project (2014) [3]
Initiating Factor	Low muscle strength (Probable Sarcopenia)	Screening tools (SARC-F, calf circ.) or low strength/performance (Possible Sarcopenia)	Low lean mass plus low strength
Staged Diagnosis	Yes: Probable, Confirmed, Severe	Yes: Possible, Confirmed, Severe	Less emphasized, but based on thresholds
Low Muscle Strength	Grip: <27kg (M), <16kg (F); Chair stand: >15s	Grip: <28kg (M), <18kg (F); Chair stand: ≥12s	Grip: <26kg (M), <16kg (F)
Low Muscle Quantity	ASM/h2 (DXA): <7.0kg/m2 (M), <6.0kg/m2 (F)	ASM/h2 (BIA): ≤7.0kg/m2 (M), ≤5.7kg/m2 (F)	ALM/BMI: <0.789 (M), <0.512 (F)
Low Physical Performance	Gait speed ≤0.8m/s; SPPB ≤8; TUG ≥20s	Gait speed <1.0m/s; 5-STS ≥12s; SPPB ≤9	Gait speed <0.8m/s
Population Focus	European/Global	Asian	Western/Global

For more detailed guidance and the foundational research on these diagnostic criteria, particularly concerning the EWGSOP2 framework, the revised consensus paper is an essential resource for clinicians and researchers: Sarcopenia: revised European consensus on definition and diagnosis [1].

Conclusion

Diagnosing sarcopenia involves a structured process that combines clinical assessment with objective measurements of muscle strength, mass, and physical performance [1, 2, 3]. While various international criteria exist, such as EWGSOP2, AWGS 2019, and FNIH, they all aim to provide a clear pathway for diagnosis and severity assessment [1, 2, 3]. The differences in specific cut-offs and methods emphasize the need for tailored approaches based on individual factors and clinical context. Early diagnosis is crucial for implementing effective interventions to manage this age-related muscle condition and enhance the well-being of seniors [1, 2].

Frequently Asked Questions

What is the simplest way to screen for sarcopenia?

The SARC-F questionnaire is a simple, quick screening tool that can be used to identify individuals at risk. A score of 4 or more suggests probable sarcopenia and warrants further investigation by a healthcare professional [1, 2].

Does everyone with sarcopenia experience functional limitations?

Not necessarily. The condition is staged based on severity. Individuals can have 'probable sarcopenia' (low muscle strength) or 'confirmed sarcopenia' (low strength and low mass) without significant functional limitations. Poor physical performance is a criterion for 'severe sarcopenia' [1, 2].

Are DXA and BIA the only ways to measure muscle mass for diagnosis?

DXA and BIA are the most common methods [1, 2, 3], but other techniques like CT scans, MRI, and even simple calf circumference measurements (as recommended by AWGS 2019 for screening) can also provide information on muscle mass [2].

Why do different diagnostic criteria exist for sarcopenia?

The differences reflect ongoing research and consensus efforts to refine the definition. Variations in methodology, cut-off points, and reference populations (e.g., Asian vs. Western) lead to different guidelines [1, 2, 3]. The choice of criteria can impact prevalence rates and is important in both clinical and research settings.

What is the difference between sarcopenia and cachexia?

While both involve muscle loss, sarcopenia is primarily a disease of aging and progressive muscle decline. Cachexia is a wasting syndrome often associated with severe chronic illness (e.g., cancer, heart failure) and is characterized by a systemic inflammatory response, significant weight loss, and anorexia.

Is sarcopenia preventable or treatable?

Yes. Prevention and management strategies include regular physical activity, particularly resistance exercise to build muscle strength, and adequate nutritional intake, especially protein. Early diagnosis is key to starting interventions that can slow the progression and mitigate the effects [1, 2].

Can doctors diagnose sarcopenia without advanced equipment?

In primary care or community settings, doctors can perform initial screening using questionnaires like SARC-F and simple physical tests like the Chair Stand test [1, 2]. If these indicate low strength, a more definitive diagnosis with advanced equipment like a DXA scan would be recommended [1].