Prevalence of sarcopenia in community-dwelling older adults using the updated EWGSOP2 definition according to kidney function and albuminuria
Authors: Moreno-Gonzalez Rafael , Corbella Xavier , Mattace-Raso Francesco , Tap Lisanne , Sieber Cornel , Freiberger Ellen , Kostka Tomasz , Guligowska Agnieszka , Melzer Itshak , Melzer Yehudit , Carlsson Axel C. , Ärnlöv Johan , Roller-Wirnsberger Regina , Wirnsberger Gerhard , Gil Pedro , Martinez Sara Lainez , Fabbietti Paolo , Corsonello Andrea , Lattanzio Fabrizia , Formiga Francesc ,   on behalf of SCOPE investigators, Lattanzio Fabrizia , Corsonello Andrea , Bustacchini Silvia , Bolognini Silvia , D’Ascoli Paola , Moresi Raffaella , Di Stefano Giuseppina , Giammarchi Cinzia , Bonfigli Anna Rita , Galeazzi Roberta , Lenci Federica , Bella Stefano Della , Bordoni Enrico , Provinciali Mauro , Giacconi Robertina , Giuli Cinzia , Postacchini Demetrio , Garasto Sabrina , Cozza Annalisa , Firmani Romano , Nacciariti Moreno , Di Rosa Mirko , Fabbietti Paolo 
Published: October 2020

Abstract
Background
Loss of muscle mass and function may be more pronounced in older adults with chronic kidney disease (CKD) and with albuminuria. Thus, we investigated the prevalence of sarcopenia among community-dwelling older adults according to kidney function and grade of albuminuria. We also explored differences in the prevalence of sarcopenia according to three different equations for the estimation of glomerular filtration rate (eGFR).

Methods
A cross-sectional analysis of 1420 community-dwelling older adults (≥75 years old) included in the SCOPE study, a multicenter prospective cohort study, was conducted. Comprehensive geriatric assessment including short physical performance battery (SPPB), handgrip strength test and bioelectrical impedance analysis (BIA) was performed. Sarcopenia was defined using the updated criteria of the European Working Group on Sarcopenia in Older People (EWGSOP2). eGFR was calculated using Berlin Initiative Study (BIS), Chronic Kidney Disease Epidemiological Collaboration (CKD-EPI) and Full Age Spectrum (FAS) equations, and urinary albumin-to-creatinine ratio (ACR) was collected to categorize CKD according to Kidney Disease Improving Global Outcomes guidelines.

Results
Median age was 79.5 years (77.0–83.0), 804 (56.6%) were women. Using EWGSOP2 definition, 150 (10.6%) participants met diagnostic criteria for sarcopenia. Moreover, 85 (6%) participants had severe sarcopenia. Sarcopenia was more prevalent in participants with more advanced stages of CKD according to BIS eq. (9.6% in stages 1 and 2 and 13.9% in stages 3a, 3b and 4, p = 0.042), and also according to CKD-EPI (9.8% vs. 14.2%, p = 0.042) and FAS although not reaching statistical signification (9.8% vs. 12.7%, p = 0.119). Thus, differences in prevalence are observed among CKD categories as estimated by different equations. Prevalence of sarcopenia was also higher with increasing albuminuria categories: 9.3% in normoalbuminuric, 13.2% in microalbuminuric and 16.8% in macroalbuminuric participants, (p = 0.019).

Conclusions
Sarcopenia is common among community-dwelling older adults, especially among those with more advanced CKD categories, with prevalence estimates differing slightly depending on the equation used for the estimation of eGFR; as well as among those with higher albuminuria categories.