Transition between 2019 and 2025 sarcopenia definitions by the Asian Working Group for Sarcopenia in community-dwelling older adults

Abstract Background The Asian Working Group for Sarcopenia (AWGS) has revised its diagnostic criteria over time, most recently in 2025. The impact of these updates on sarcopenia classification in real-world Asian populations has not been fully established. This study compared the characteristics and diagnostic transitions of community-dwelling older adults between the 2019 and 2025 definitions. Methods We conducted a secondary analysis of a nationwide epidemiological study of community-dwelling Thai adults aged ≥ 60 years. Muscle mass was measured using bioelectrical impedance analysis, handgrip strength with a digital dynamometer and physical performance using gait speed, five-times sit-to-stand and timed up-and-go tests. Sarcopenia was classified according to AWGS 2019 and 2025 definitions. Diagnostic transitions between the 2019 and 2025 criteria were visualized using a Sankey diagram. Characteristics and functional measures were then compared between concordant and reclassified groups. Results From overall 2,456 subjects (Male: Female = 894: 1,562), sarcopenia prevalence increased following the AWGS definition update (18.1% in 2019 vs. 28.3% in 2025; p < 0.001). The AWGS 2025 definition identified more individuals with higher BMI and those aged < 65 years, while functional profiles remained comparable to those identified by the 2019 definition. For possible sarcopenia, prevalence decreased substantially under AWGS 2025 compared with AWGS 2019 (51.2% vs. 93.7%; p < 0.001). Diagnostic transition analysis showed that 14.9% of participants were newly classified as sarcopenic under AWGS 2025, while 4.7% were reclassified as non-sarcopenia. Characteristics and functional profiles of the reclassified sarcopenia group were similar to the concordant sarcopenia group, though long-term clinical outcomes remain to be established. Participants reclassified to non-sarcopenia showed no clear distinction from either concordant group, signaling potential diagnostic overlap at the margins. Conclusions The AWGS 2025 criteria identify a broader population with sarcopenia, including younger individuals and those with higher BMI, while remaining largely consistent with the AWGS 2019 diagnostic definition. While these similarities suggest that the updated framework may enhance sensitivity to detect individuals with underlying vulnerabilities, further prospective studies are required to determine if these newly captured individuals experience true, long-term adverse clinical outcomes or if this expansion introduces a risk of diagnostic overcounting. The observed ambiguity in those reclassified as non-sarcopenic further highlights that while the updated framework may improve practical applicability, a clear line between high-risk phenotype and overdiagnosis remains difficult to draw using cross-sectional indices alone. The findings of this study are limited to individuals aged ≥ 60 years, and the application of the 2025 criteria to younger populations requires further investigation. Longitudinal studies are also needed to refine age-specific cut-offs and to clarify the clinical significance of individuals near diagnostic thresholds.