What are the Asian Working Group for Sarcopenia (AWGS) diagnostic criteria and first‑line management for sarcopenia?

Asian Working Group for Sarcopenia (AWGS) Diagnostic Criteria and Management

Diagnostic Criteria

The AWGS 2019 consensus defines sarcopenia as age-related loss of muscle mass plus low muscle strength and/or low physical performance, with specific cutoff values established for Asian populations. 1

Screening and Case-Finding (Primary Care Settings)

The AWGS 2019 algorithm begins with initial screening using one of the following tools: 2, 1

• Calf circumference: <34 cm in men, <33 cm in women 2, 1
• SARC-F questionnaire: Score ≥4 2, 1
• SARC-CalF: Score ≥11 1

Diagnostic Components

If screening is positive, proceed with assessment of the following three components: 1, 3

1. Low Muscle Strength

• Handgrip strength: <28 kg for men, <18 kg for women 1
• 5-time chair stand test: ≥12 seconds 1

2. Low Physical Performance

Any of the following criteria: 1

• 6-meter walk speed: <1.0 m/s
• Short Physical Performance Battery (SPPB): Score ≤9
• 5-time chair stand test: ≥12 seconds

3. Low Muscle Mass

Height-adjusted muscle mass cutoffs: 1, 3

• Dual-energy X-ray absorptiometry (DXA): <7.0 kg/m² in men, <5.4 kg/m² in women
• Bioelectrical impedance analysis (BIA): <7.0 kg/m² in men, <5.7 kg/m² in women

Diagnostic Categories

"Possible sarcopenia" is diagnosed when either low muscle strength OR low physical performance is present alone, specifically for use in primary care settings to enable earlier lifestyle interventions. 1

Confirmed sarcopenia requires low muscle mass PLUS either low muscle strength or low physical performance. 1, 3

Severe sarcopenia is diagnosed when all three components are present (low muscle mass, low muscle strength, AND low physical performance). 3

Clinical Significance of Different Diagnostic Combinations

Research demonstrates that sarcopenia defined by both low muscle mass AND low physical performance (rather than low muscle strength) has superior predictive validity for adverse outcomes: 4

• Increased risk of mobility disability (OR 2.14) and falls (OR 1.74) 4
• When using SPPB specifically for physical performance assessment, increased risk of falls with fracture (OR 2.53) and IADL disabilities (OR 2.77) 4
• Sarcopenia defined only by low muscle mass and low handgrip strength showed no associations with incident adverse health outcomes 4

First-Line Management

Exercise Interventions

Progressive resistance (strength) training is the cornerstone first-line therapy for sarcopenia management. 2, 5

• Frequency: 2-3 times per week 5
• Expected outcomes: Approximately 1.5 kg gain in muscle mass over 12 weeks 5
• Combine with aerobic activity and weight-bearing exercise when safely feasible 5

Nutritional Management

Protein intake must be increased to at least 1.2 g/kg/day as a minimum threshold for older adults with sarcopenia. 2

• Protein distribution: 20-30g per meal, distributed throughout the day 5
• Protein source: Preferably leucine-rich protein sources 5
• This threshold can be increased in the presence of catabolic conditions or muscle wasting 2

Specific Nutritional Supplements

• Leucine supplementation: A branched-chain amino acid essential for protein synthesis and skeletal muscle synthesis 2
• Combined supplementation: Diet or nutritional supplements should be combined with exercise intervention (conditional recommendation) 2
• Vitamin D and omega-3 fatty acids: Ensure adequate intake to prevent sarcopenia progression 5
• B vitamins: Address deficiencies that may affect neuromuscular function 5
• Fruits and vegetables: Higher intake associated with greater muscle mass and strength 5

Critical Implementation Points

No medication is currently available to treat sarcopenia, making exercise and nutrition essential. 2

The AWGS 2019 specifically recommends that individuals diagnosed with "possible sarcopenia" should start lifestyle interventions and related health education immediately in primary healthcare settings. 2, 1

Common Pitfalls to Avoid

• Never focus solely on muscle mass measurement without assessing functional components (strength or performance), as this has limited predictive validity for adverse outcomes 4
• Avoid inadequate protein intake during any treatment phase, which is the most common modifiable factor compromising sarcopenia management 5
• Do not neglect resistance training, which is essential for maintaining and building muscle mass 5
• Never address sarcopenia without simultaneously implementing both exercise and nutritional interventions, as the multifactorial etiology requires comprehensive management 5