Changes of sarcopenia case finding by different Asian Working Group for Sarcopenia in community indwelling middle-aged and old people

Frontiers in sarcopenia: Advancements in diagnostics, molecular mechanisms, and therapeutic strategies

The onset of sarcopenia is intimately linked with aging, posing significant implications not only for individual patient quality of life but also for the broader societal healthcare framework. Early and accurate identification of sarcopenia and a comprehensive understanding of its mechanistic underpinnings and therapeutic targets paramount to addressing this condition effectively. This review endeavors to present a cohesive overview of recent advancements in sarcopenia research and diagnosis. We initially delve into the contemporary diagnostic criteria, specifically referencing the European Working Group on Sarcopenia in Older People (EWGSOP) 2 and Asian Working Group on Sarcopenia (AWGS) 2019 benchmarks. Additionally, we elucidate comprehensive assessment techniques for muscle strength, quantity, and physical performance, highlighting tools such as grip strength, chair stand test, dual-energy X-ray Absorptiometry (DEXA), bioelectrical impedance analysis (BIA), gait speed, and short physical performance battery (SPPB), while also discussing their inherent advantages and limitations. Such diagnostic advancements pave the way for early identification and unequivocal diagnosis of sarcopenia. Proceeding further, we provide a deep-dive into sarcopenia's pathogenesis, offering a thorough examination of associated signaling pathways like the Myostatin, AMP-activated protein kinase (AMPK), insulin/IGF-1 Signaling (IIS), and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways. Each pathway's role in sarcopenia mediation is detailed, underscoring potential therapeutic target avenues. From a mechanistic perspective, the review also underscores the pivotal role of mitochondrial dysfunction in sarcopenia, emphasizing elements such as mitochondrial oxidative overload, mitochondrial biogenesis, and mitophagy, and highlighting their therapeutic significance. At last, we capture recent strides made in sarcopenia treatment, ranging from nutritional and exercise interventions to potential pharmacological and supplementation strategies. In sum, this review meticulously synthesizes the latest scientific developments in sarcopenia, aiming to enhance diagnostic precision in clinical practice and provide comprehensive insights into refined mechanistic targets and innovative therapeutic interventions, ultimately contributing to optimized patient care and advancements in the field.

Phenotype validation of the Korean working group on sarcopenia guideline

BACKGROUND

This study aimed to validate the proposed Korean Working Group on Sarcopenia (KWGS) guideline, which introduces the concept of functional sarcopenia, in older Korean adults.

METHODS

Data from the Aging Study of Pyeongchang Rural Area, a longitudinal cohort of community-dwelling older adults, were utilized to compare frailty status and institutionalization-free survival among participants according to sarcopenia status. Based on the KWGS guideline, severe sarcopenia was defined as low muscle mass and strength with slow gait speed; sarcopenia (not severe) was defined as low muscle mass with low muscle strength or slow gait speed; and functional sarcopenia was defined as low muscle strength and slow gait speed without low muscle mass.

RESULTS

Among the 1302 participants, 329 (25.3 %) had severe sarcopenia, 147 (11.3 %) had sarcopenia (not severe), and 277 (21.3 %) had functional sarcopenia. Frailty was significantly greater in participants with any phenotype of sarcopenia than in those without sarcopenia. Additionally, participants with functional sarcopenia were frailer than those with sarcopenia (not severe). Furthermore, the rates of institutionalization and mortality were higher in participants with any phenotype of sarcopenia than in those without sarcopenia. There was no statistical difference between the rates of sarcopenia (not severe) and those with functional sarcopenia. These findings remained consistent after adjusting for age and sex.

CONCLUSIONS

Each phenotype according to the KWGS guideline was associated with significantly greater frailty and increased risk of institutionalization and mortality. Functional sarcopenia was associated with greater frailty and had comparable prognosis with sarcopenia (not severe).

Long-Term Mortality Risk in Older Adults with Sarcopenia: An 11-Year Prospective Cohort Study Comparing AWGS 2014 and AWGS 2019 Guidelines for Enhanced Clinical Utility and Accurate Risk Prediction

OBJECTIVES

To discern the diagnostic accuracy between the updated diagnostic consensus of the Asian Working Group for Sarcopenia (AWGS) in 2019 (AWGS 2019) and the previous AWGS 2014 guidelines.

DESIGN

A prospective population-based cohort study.

SETTING AND PARTICIPANTS

The study included 731 older community-dwelling adults aged ≥ 65 years who participated in face-to-face interviews and were followed up for 11-year mortality until 31 Mar 2022.

MEASUREMENTS

We utilized a handgrip strength dynamometer to measure participants' muscle strength, while their walking speed was determined by a timed 6-meter walk test at their usual pace. Additionally, muscle mass was measured using dual-energy X-ray absorptiometry scanning. Sarcopenia was defined as the presence of low muscle mass in combination with weakness and/or slowness both by AWGS 2014 and 2019 criteria.

RESULTS

The present study followed 731 participants (mean age 73.4 ± 5.4 years, men predominant 52.8%) over a period of 11 years, yielding 5927 person-years and 159 deaths. Prevalence of sarcopenia defined by AWGS 2019 and 2014 criteria were 8.5% and 6.8%, respectively. Sarcopenia defined by AWGS 2019 (HR 1.62, 95% CI 1.04-2.54, p=0.034) but not AWGS 2014 was significantly associated with mortality in community-living older adults after adjusting for potential confounders such as age, sex, education, drinking, disease burden and serum level of testosterone. The study also found that the AWGS 2019 criteria had a better model fitness than AWGS 2014 criteria in predicting mortality.

CONCLUSION

AWGS 2019 criteria outperformed AWGS 2014 in identifying sarcopenia risk and predicting mortality. Screening for sarcopenia in older adults may improve health outcomes by identifying those at increased mortality risk.