Background:Patients with rheumatoid arthritis (RA) were at risk for altered body composition with higher prevalence of sarcopenia compared to the general population. Low lean muscle mass may constitute an additional risk factor for altered bone density in RA patients.Objectives:We aimed to study the prevalence of sarcopenia and to assess its predictive factors in Moroccan patients with RA.Methods:We conducted a cross-sectional study over two months in our department of rheumatology. All RA patients fulfilled ACR/EULAR 2010 criteria. We performed a whole-body dual-energy X-ray absorptiometry (DXA) to measure lean mass, fat mass and bone mass in the whole body and body parts. The appendicular skeletal muscle mass was assessed using the sum of skeletal muscle mass in the arms and legs. The relative skeletal muscle mass index (RSMI) was calculated from the appendicular skeletal mass divided by the square of the patient’s height (kg/m2). According to Baumgartner et al, sarcopenia was defined as a relative SMI <5.5 kg/m2on women and <7.26 kg/m2on men. Body mass index (BMI) was measured and patients were classified according to World Health Organization. Disease activity and functional disability were measured using the 28-joint Disease Activity Score (DAS28) with CRP and the Health Assessment Questionnaire (HAQ). Comorbidities and medication use including corticosteroids were also recorded. Data was entered and processed using the IBM SPSS Statistics 20. A univariate analysis as well as multivariate regressions were carried out to assess the association between sarcopenia and lumbar spine and femoral neck (FN) bone mineral density (BMD) and RA characteristics.Results:We included 70 (87.5%) women and 10 (12.5%) men with a mean age of 53.59 ±10.96 years old. They had a mean disease duration of 12.35± 8.68, a mean DAS 28 CRP of 2.64±1.34, a mean HAQ of 0.94±0.63 and a mean RSMI of 5.75±1.17. Women had a mean RSMI of 6.33±1.04 while men had a mean RSMI of 5.66±1.17. The prevalence of sarcopenia in our population was 47.4% (37), of whom 81.1% (30) women.In univariate regression analysis, sarcopenia was associated with normal BMI (OR: 8.59, 95% CI [3.054-24.182], p= 0.000), DAS 28 CRP (OR: 1.78, 95% CI [1.203-2.657], p= 0.004), HAQ (OR: 2.15, 95% CI [1.165-5.433], p= 0.019), lumbar spine BMD (OR: 0.001, 95% CI [0.00001-0.043], p= 0.0004) and FN BMD (OR: 0.000006, 95% CI [0.000-0.002], p= 0,00008 at right FN and OR: 0.00009, 95% CI [0.000001-0.010], p=0.000 at left FN, respectively).In multiple regression analysis, sarcopenia was associated with normal BMI (OR: 11.56, 95% CI [2.754–48.598]), p=0.001 and FN BMD (OR: 0.00, 95% CI [0.000–0.084], p = 0.006).Conclusion:In the present study, sarcopenia was common among RA patients and associated with normal BMI and femoral neck BMD, emphasizing the importance of this modifiable risk factor. Further studies are needed to identify effective means to improve lean muscle mass in patients with RA.References:[1]Mochizuki T et al. Sarcopenia-associated factors in Japanese patients with rheumatoid arthritis: A cross-sectional study. Geriatr. Gerontol. Int. 2019;19 (9), 907-912[2]Okano T et al. Loss of lean body mass affects low bone mineral density in patients with rheumatoid arthritis -results from the TOMORROW study-, Modern Rheumatology. 2017;27(6):1-19.[4]Peggy M. Cawthon. Assessment of Lean Mass and Physical Performance in Sarcopenia. Journal of Clinical Densitometry. 2015;18(4):467-71.Disclosure of Interests:None declared
Association between skeletal muscle mass and mammographic breast density
