The Conceptual Definition of Sarcopenia: Delphi Consensus from the Global Leadership Initiative in Sarcopenia (GLIS)
Authors: Kirk Ben , Cawthon Peggy M , Arai Hidenori , Ávila-Funes José A , Barazzoni Rocco , Bhasin Shalender , Binder Ellen F , Bruyere Olivier , Cederholm Tommy , Chen Liang-Kung , Cooper Cyrus , Duque Gustavo , Fielding Roger A , Guralnik Jack , Kiel Douglas P , Landi Francesco , Reginster Jean-Yves , Sayer Avan A , Visser Marjolein , von Haehling Stephan , Woo Jean , Cruz-Jentoft Alfonso J ,   The Global Leadership Initiative in Sarcopenia (GLIS) group, Júnior Alberto Frisoli , Maier Andrea Britta , Newman Anne B , De Spiegeleer Anton , Granic Antoneta , Cherubini Antonio , AlAbdulKader Assim , Beaudart Charlotte , Clark Brian , Brown Todd , Prado Carla , Greig Carolyn , Won Won Chang , Suetta Charlotte , Liang Chih-Kuang , Hurst Christopher , Rooks Daniel , Le Couteur David , Scott David , Waters Debra , Sanchez-Rodriguez Dolores , Reijnierse Esmee , Topinková Eva , Petermann Fanny , Callaghan Martin Finbarr , Bahat Gülistan , Alhmly Haya , Aprahamian Ivan , Lim Jae-Young , Michel Jean-Pierre , Zanker Jesse , Batsis John , Kanis John , Lewis Joshua , Bauer Juergen , Pasco Julie , Keogh Justin , Pitkala Kaisu , Madden Ken , Toba Kenji , Norman Kristina , Schaap Laura , Kang Lin , Peng Li-Ning , Micklesfield Lisa , CPGM de Groot Lisette , Donini Lorenzo M , Sim Marc , Gonzalez Maria Cristina , Essomba Marie-Josiane Ntsama , Kuzuya Masafumi , Grossmann Mathis , Cesari Matteo , Tieland Michael , Witham Miles , Chou Ming-Yueh , Yamada Minoru , Grounds Miranda , Soler Pedro Abizanda , Xue Qianli , Cooper Rachel , Wirth Rainer , Visvanathan Renuka , Merchant Reshma Aziz , Rizzoli Rene , Daly Robin , Kalula Sebastiana , Robinson Sian , perkisas Stany , Schneider Stéphane , Heymsfield Steven B , Phu Steven , Phillips Stuart , Kim Sunyoung , Pereira Suzette , Gill Thomas , Grodzicki Tomasz , Kostka Tomasz , Auyeung Tungwai , Lim Wee-Shiong , Lee Wei-Ju , Algindan Yasmin , Yamada Yosuke , Lee Yunhwan , Boirie Yves , Luiking Yvette 
Published: March 2024

Abstract

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 (&gt;80%), moderate agreement (70–80%) and low agreement (&lt;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.