SARCOSPA - Sarcopenia in spondyloarthritis patients

INTRODUCTION: The loss of muscle mass (MM) is a serious problem which has been demonstrated in patients with rheumatoid arthritis. There are few studies about the loss of MM in patients with spondyloarthritis (Spa). OBJECTIVE: To assess muscle mass index (MMI) in a cohort of patients with Spa and compare it with a control group of healthy individuals; to verify if a higher risk of sarcopenia is related with disease activity, functional impairment, duration of the illness and radiological damage. METHODS: Case control study. Muscle mass index (MMI) was determined, from the value of MM, using Lee’s equation, in a cohort of patients with spondyloarthritis and in a control group. Bath Ankylosing Spondylitis Disease Activity and Function Indexes (BASDAI and BASFI), Ankylosing Spondylitis Quality of Life (ASQoL) and Modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) were assessed in a cohort of patients with axial Spa, as well as Health Assessment Questionnaire (HAQ) and Disease Activity Score 28 (DAS28) in patients with peripheral disease. Data were treated using SPSS version 17.0. Values of p<0,05 were considered with statistical significance. RESULTS: 60 patients were enrolled; 48.2% were males, mean age 45.5±13.4 years, mean disease duration 10.9±11.6 years; 36 had ankylosing spondylitis and 24 had psoriatic arthritis. 62% of patients had sarcopenia and there was a significant difference in mean MMI between patients and controls (7.65±0.98 vs 8.25±0.92; p=0.001, OR =5.23. In male patients, there was a statistically significant moderate negative correlation between MMI and BASDAI and BASFI (p=-0.536 and p=-0.445). No other significant correlations were identified. CONCLUSION: Our study supports the hypothesis of a greater prevalence of sarcopenia in patients with Spa compared to healthy controls. Some limitations included the sample size, potential confounding factor such the bias of measurement and the use of a non-validated equation to Portuguese population to calculate MM.