MUSCLE ULTRASOUND FOR THE DIAGNOSIS OF SARCOPENIA IN RHEUMATOID ARTHRITIS (RA).

Abstract

Background: Sarcopenia is a muscular disease characterized by a loss of muscle mass and function. The condition is associated with chronic diseases and ageing and predicts disability, hospitalization and death (1). Due to chronicity and disability produced by RA, it is convenient to see the relationship with sarcopenia. Objectives: To assess the diagnostic utility of ultrasound (US) for sarcopenia. Methods: Cases: Outpatients, 65 years old or more, with RA (ACR/EULAR 2010 criteria) from the rheumatology clinics of 4 Spanish University Hospitals were randomly selected consecutively from rheumatology consultation since May 2021 to September 2021. Controls: Control subjects without rheumatoid disease were selected from family members or friends of the cases, paired by age, gender and social status from May to September 2021. Variable and measures: The main evaluated outcome was sarcopenia as defined in 2019 by the European Working Group on Sarcopenia in Older People (EWGSOP). Crossectional Ultrasounds (US) of the third proximal forearm were evaluated for the perpendicular distance (milimetres) between superficial surface of subcutaneous celular tissue and the deep surface close to the ulnae with two different measures (66% and 75%). Crossectional US images were also obtained of lower limbs, at an equidistant point between anterosuperior iliac spine and the upper border of the patella for measuring the distance between superficial surface of subcutaneous celular tissue and the deep interface of the femur with vastus medialis muscle with two different measures (50% and 75%). Handheld dynamometer was used to measure the strength in upper limbs. Body composition was evaluated using dual-energy X-ray densitometry.