The Relationship Between Sarcopenic Obesity and Knee Osteoarthritis: The SARCOB Study

Background: To investigate whether sarcopenic obesity may contribute to knee osteoarthritis or not. Methods: In this study, we assessed 140 community-dwelling adult patients. Their demographic data were recorded along with comorbidities. Anterior mid-thigh muscle thickness in the axial plane was measured on the dominant leg using ultrasound midway between the anterior superior iliac spine and the upper end of patella in millimeter. Then, the sonographic thigh adjustment ratio was calculated by dividing this thickness by body mass index. ISarcoPRM algorithm was used for the diagnosis of sarcopenia. Kellgren-Lawrence grading was used for knee osteoarthritis. Functional evaluation was performed using chair stand test, gait speed, and grip strength. Results: There were 50 patients with knee osteoarthritis and 90 age- and gender-similar control subjects. When compared with controls, anterior thigh muscle thickness, gait speed, and grip strength were found to be similar between the groups, whereas body mass index and chair stand test values were higher in the knee osteoarthritis group (both P <.05). In addition, sarcopenic obesity was observed in 12 (13.3%) of control subjects and in 14 (28%) of osteoarthritis patients. When age, gender, exercise, smoking, and body composition type (i.e., nonsarcopenic nonobese, sarcopenic only, obese only, and sarcopenic obesity) were taken into binary logistic regression analyses, only sarcopenic obesity [relative risk ratio = 2.705 (95% CI: 1.079-6.779)] was independently related with the knee osteoarthritis (P <.05). Conclusion: Our preliminary study has shown that neither sarcopenia nor obesity but sarcopenic obesity seems to be independently related to the knee osteoarthritis. Further longitudinal studies with larger samples are required for investigating the effects of obesity and sarcopenia on the development of knee osteoarthritis.