Diagnosing sarcopenia: turn your eyes back on patients

The Conceptual Definition of Sarcopenia: Delphi Consensus from the Global Leadership Initiative in Sarcopenia (GLIS)

IMPORTANCE

Sarcopenia, the age-related loss of muscle mass and strength/function, is an important clinical condition. However, no international consensus on the definition exists.

OBJECTIVE

The Global Leadership Initiative in Sarcopenia (GLIS) aimed to address this by establishing the global conceptual definition of sarcopenia.

DESIGN

The GLIS steering committee was formed in 2019-21 with representatives from all relevant scientific societies worldwide. During this time, the steering committee developed a set of statements on the topic and invited members from these societies to participate in a two-phase International Delphi Study. Between 2022 and 2023, participants ranked their agreement with a set of statements using an online survey tool (SurveyMonkey). Statements were categorised based on predefined thresholds: strong agreement (>80%), moderate agreement (70-80%) and low agreement (<70%). Statements with strong agreement were accepted, statements with low agreement were rejected and those with moderate agreement were reintroduced until consensus was reached.

RESULTS

107 participants (mean age: 54 ± 12 years [1 missing age], 64% men) from 29 countries across 7 continents/regions completed the Delphi survey. Twenty statements were found to have a strong agreement. These included; 6 statements on 'general aspects of sarcopenia' (strongest agreement: the prevalence of sarcopenia increases with age (98.3%)), 3 statements on 'components of sarcopenia' (muscle mass (89.4%), muscle strength (93.1%) and muscle-specific strength (80.8%) should all be a part of the conceptual definition of sarcopenia)) and 11 statements on 'outcomes of sarcopenia' (strongest agreement: sarcopenia increases the risk of impaired physical performance (97.9%)). A key finding of the Delphi survey was that muscle mass, muscle strength and muscle-specific strength were all accepted as 'components of sarcopenia', whereas impaired physical performance was accepted as an 'outcome' rather than a 'component' of sarcopenia.

CONCLUSION AND RELEVANCE

The GLIS has created the first global conceptual definition of sarcopenia, which will now serve to develop an operational definition for clinical and research settings.

Bioelectrical impedance analysis in the BaSAlt cohort-study: the phase angle as an additional parameter for sarcopenia quantification among German nursing home residents?

PURPOSE

Sarcopenia is characterized by the loss of muscle mass, strength, and physical functioning. The bioelectrical impedance analysis (BIA) is a simplify method for the measurement of muscle quantity and quality. But there is a lack of evidence in the interpretation of the muscle quality parameter phase angle (PhA), which was recommended by the European Working Group on Sarcopenia in Older People 2 (EWGSOP2). We hypothesize that the PhA shows differences between sarcopenia categorized groups and can be used as an additional parameter for sarcopenia quantification among residents of nursing homes (NH).

METHODS

Based on EWGSOP2 specifications, 78 residents from five German NH was categorized into sarcopenia groups. Group comparisons with Kruskal-Wallis tests, Dunn-Bonferroni post-hoc-Tests, and correlations with Spearman coefficients were conducted with the muscle quality parameter PhA.

RESULTS

Significant group differences by Kruskal-Wallis test for PhA was detected (H = 8.150, p = 0.017). The Dunn-Bonferroni post-hoc-Test showed significant results by group comparison for "confirmed/ severe sarcopenia" (4.1° [3.1-5.0]) with "no sarcopenia" (4.6° [3.7-11.2]; p =0 .049) and "probable sarcopenia" (4.7° [3.4-13.5]; p = 0.016), respectively.

CONCLUSIONS

There is a limitation for differentiation in preliminary stage of sarcopenia among multimorbid NH residents by PhA. Moreover, further research for specific cut-off-values and the individual sarcopenia progression monitoring by PhA are needed.

TRIAL REGISTRATION

No. AZ A2.5.4-096_aa (Date of approval: July 2019).

"SARCOPENIA MEASURED BY ULTRASOUND IN HOSPITALIZED OLDER ADULTS" (ECOSARC): multi-centre, prospective observational study protocol

BACKGROUND

Measurement of muscle mass and function, and thereafter, screening and diagnosis of sarcopenia, is a challenge and a need in hospitalized older adults. However, it is difficult in complex real-world old patients, because usually they are unable to collaborate with clinical, functional, and imaging testing. Ultrasound measurement of quadriceps rectus femoris (QRF) provides a non-invasive, real-time assessment of muscle quantity and quality, and is highly acceptable to participants with excellent inter-rater and intra-rater variability. However, normative data, protocol standardization, and association with longitudinal outcomes, needs further research and consensus.

METHODS

Prospective exploratory multicenter study in older adults admitted to Acute Geriatric Units (AGUs) for medical reasons. 157 subjects from 7 AGUs of Spain were recruited between May 2019 and January 2022. Muscle ultrasound measurements of the anterior vastus of the QRF were acquired on admission and on discharge, using a previously validated protocol, using a Chieson model ECO2 ultrasound system (Chieson Medical Technologies, Co. Ltd, Wimxu District Wuxi, Jiangsu, China). Measurements included the cross-sectional area, muscle thickness in longitudinal view, intramuscular central tendon thickness, echogenicity, and the presence or absence of edema and fasciculations. Functional, nutritional, and DXA measurements were provided. Clinical follow-up was completed at discharge, and 30 and 90 days after discharge. Variations between hospital admission and discharge ultrasound values, and the relationship with clinical variables, will be analyzed using paired t-tests, Wilcoxon tests, or Mc Nemar chi-square tests when necessary. Prevalence of sarcopenia will be calculated, as well as sensitivity and specificity of ultrasound measurements to determine sarcopenia. Kappa analysis will be used to analyze the concordance between measurements, and sensitivity analysis will be conducted for each participating center.

DISCUSSION

The results obtained will be of great interest to the scientific geriatric community to assess the utility and validity of ultrasound measurements for the detection and follow-up of sarcopenia in hospitalized older adults, and its association with adverse outcomes.

TRIAL REGISTRATION

NCT05113758. Registration date: November 9th 2021. Retrospectively registered.

Grip Strength and Sarcopenia Predict 2-Year Cognitive Impairment in Community-Dwelling Older Adults

OBJECTIVES

Using the Asian Working Group for Sarcopenia (AWGS2019) and the European Working Group on Sarcopenia in Older People (EWGSOP2) criteria, this study examined associations of sarcopenia and its components with specific domains of cognitive impairment over time.

DESIGN

A prospective cohort study with a 2-year follow-up.

SETTING AND PARTICIPANTS

This study is part of the Taiwan Initiatives for Geriatric Epidemiological Research (TIGER), which recruited participants aged 65 years old who attended the senior health checkup program at National Taiwan University Hospital (NTUH).

METHODS

Grip strength was measured using a handgrip dynamometer. Walking speed (m/s) was measured as the time required to walk 8 feet. Muscle mass was measured by performing a bioelectrical impedance analysis. Global cognition (assessed using the Taiwanese version of the Montreal Cognitive Assessment) and 4 cognitive domains (memory, executive function, verbal fluency, and attention) were assessed over time. Associations of sarcopenia and its components with cognitive impairment were evaluated after stratification by sex using generalized linear mixed models adjusted for essential covariates for cognitive impairment.

RESULTS

Compared with robust women, those with severe sarcopenia were more likely to have a global cognitive impairment over time (β = -0.87, P = .03 based on AWGS2019 criteria and β = -1.07, P = .02 based on the EWGSOP2 criteria). Among men, low grip strength was associated with poor scores on measures of global cognition (β = -0.80, P = .03), executive function (β = -0.35, P = .001), verbal fluency (β = -0.31, P = .02), and attention (β = -0.34, P = .008) over time.

CONCLUSIONS AND IMPLICATIONS

Severe sarcopenia predicted global and specific domains of cognitive impairment in older adults. Poor grip strength predicted cognitive impairment in men but not in women. A screen for sarcopenia severity and low muscle strength may be used to identify the risk of cognitive impairment.

Clinical evaluation of automated segmentation for body composition analysis on abdominal L3 CT slices in polytrauma patients

INTRODUCTION

Sarcopenia is a muscle disease that involves loss of muscle strength and physical function and is associated with adverse health effects. Even though sarcopenia has attracted increasing attention in the literature, many research findings have not yet been translated into clinical practice. In this article, we aim to validate a deep learning neural network for automated segmentation of L3 CT slices and aim to explore the potential for clinical utilization of such a tool for clinical practice.

MATERIALS AND METHODS

A deep learning neural network was trained on a multi-centre collection of 3413 abdominal cancer surgery subjects to automatically segment muscle, subcutaneous and visceral adipose tissue at the L3 lumbar vertebral level. 536 Polytrauma subjects were used as an independent test set to show generalizability. The Dice Similarity Coefficient was calculated to validate the geometric similarity. Quantitative agreement was quantified using Bland-Altman's Limits of Agreement interval and Lin's Concordance Correlation Coefficient. To determine the potential clinical usability, randomly selected segmentation images were presented to a panel of experienced clinicians to rate on a Likert scale.

RESULTS

Deep learning results gave excellent agreement versus a human expert operator for all of the body composition indices, with Concordance Correlation Coefficient for skeletal muscle index of 0.92, Skeletal muscle radiation attenuation 0.94, Visceral Adipose Tissue index 0.99 and Subcutaneous Adipose Tissue Index 0.99. Triple-blinded visual assessment of segmentation by clinicians correlated only to the Dice coefficient, but had no association to quantitative body composition metrics which were accurate irrespective of clinicians' visual rating.

CONCLUSION

A deep learning method for automatic segmentation of truncal muscle, visceral and subcutaneous adipose tissue on individual L3 CT slices has been independently validated against expert human-generated results for an enlarged polytrauma registry dataset. Time efficiency, consistency and high accuracy relative to human experts suggest that quantitative body composition analysis with deep learning should is a promising tool for clinical application in a hospital setting.

The Diagnostic Value of Ultrasound of the Rectus Femoris for the diagnosis of Sarcopenia in adults: A systematic review

BACKGROUND & AIM

Sarcopenia is defined as a loss of muscle mass and function, which can be caused by normal ageing or factors such as physical inactivity. Severe health consequences caused by sarcopenia highlight the need for early identification. Computed Tomography (CT) imaging, often mentioned as the gold standard due to its accuracy, is costly and not routinely performed in daily clinical care. Ultrasound of the rectus femoris, however, is low in costs and easily accessible. The aim is to present the current and most recent literature regarding the diagnostic value of ultrasound measurements of the rectus femoris for the diagnosis of sarcopenia in adults.

METHODS

The databases PubMed and Web of Science were used to search for studies comparing ultrasound of the rectus femoris with a reference test to diagnose sarcopenia in adults. The quality of the final eligible studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies, version 2, tool (QUADAS-2).

RESULTS

Six studies were included in this systematic review. The muscle thickness and cross-sectional area of the rectus femoris were assessed and compared with the reference tests CT, Dual-Energy X-ray Absorptiometry (DXA), and Bioelectrical Impedance Analysis (BIA). Half of the studies had a low risk of bias on all QUADAS-2 domains. Three studies reported statistical significant outcomes and diagnostic values ranging from 60 to 81% sensitivity and 51 to 94% specificity.

CONCLUSIONS

Ultrasound of the rectus femoris muscle to diagnose sarcopenia has been shown to be a promising method in multiple clinical populations. However, there were some limitations such as a high methodological heterogeneity. Future research should develop standardized protocols and determine clear cut-off values to allow for a better implementation of ultrasound in clinical practice.