Prevalence of sarcopenic obesity in adults with end-stage knee osteoarthritis

Objective: To identify the prevalence of sarcopenic obesity, a phenotype of low muscle mass and high adiposity, in adults with end-stage knee osteoarthritis (OA). Various diagnostic criteria, including assessment of muscle/fat mass, muscle strength and physical function, were used to identify patients with and without sarcopenic obesity, and to compare outcomes of pain, function and quality of life. Design: Cross-sectional clinical study including adults with a body mass index (BMI) >= 30 kg/m(2) and knee OA. Body composition was measured by dual-energy X-ray absorptiometry (DXA). Assessments included gait speed, handgrip strength, six minute walk test, and self-reported pain, physical function, and health-related quality of life using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and EuroQol Foundation (EQ-5D). Results: 151 adults (59% female) aged 65.1 +/- 7.9 years, mean BMI 37.1 +/- 5.5 kg/m(2), were included. Prevalence of sarcopenic obesity using diagnostic cut-offs of appendicular skeletal muscle mass (ASM) relevant to height(2), weight and BMI varied from 1.3% (95% confidence interval (CI): 0.2-4.7%) to 14.6% (9.4-21.2%) and 27.2% (20.2-35%), respectively. A combined diagnostic approach including low ASM with either low strength or low function yielded a prevalence of 8.6% (4.7-14.3%). Sarcopenic obesity influenced walking speed, endurance, strength, and patient-reported difficulty with self-care activities, regardless of diagnostic approach. Conclusion: Prevalence of sarcopenic obesity varied depending on diagnostic criteria. Given the impact of this condition and OA on physical function, we suggest a combined diagnostic approach be used to clarify expected prevalence and enable early clinical identification and management of sarcopenic obesity in patients with knee OA. (C) 2019 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.