Ab1182 Muscle Strength Could Be Determined by Age, Dlcoc and Health Assessment Questionnaire in Systemic Sclerosis: A Cross-Sectional Study

Background: Patients with systemic sclerosis (SSc) are particularly susceptible to dynapenia1, characterized by low muscle strength and associated with worse clinical features, including frailty and mortality2. Objectives: To verify muscle strength (dynapenia) and its associations with clinical features in SSc. Methods: Patients with SSc according to ACR/EULAR 2013 criteria were consecutively enrolled between 2022-2023. Modified Rodnan's skin score (mRSS), EUSTAR activity index, C-reactive protein (CRP), and pulmonary function tests Forced Vital Capacity (FVC) and diffusing capacity of the lungs for carbon monoxide (DLCOc) as a percentage of predicted were calculated from the electronic medical record. Muscle strength was assessed by the 5-repetition chair stand test and dynapenia was defined according to the European Working Group on Sarcopenia in Older People 2 (chair stand test >15 seconds). Physical function was assessed by the Health Assessment Questionnaire (HAQ). Pearson's or Spearman's correlation coefficients and linear regression analyses were explored (p Results: 100 SSc patients (91 women) were included. The mean age was 60.1±11.5 years old, and the median disease duration was 11.5 (5.0-20.3) years. Diffuse cutaneous SSc was observed in 23%, while 61% had limited cutaneous SSc, and 16% had sine scleroderma SSc. The median mRSS was 4.0 (2.0-9.0) and the EUSTAR index was 1.8 (1.0-3.3). The median of CRP (mg/L) was 3.2 (1.4-7.2), pulmonary function tests showed a mean of 82.2 ± 23.6 by FVC% and 58.0 ± 20.0 by DLCOc%. Physical function had a mean HAQ score of 0.8 (0.4-1.4). In the chair stand test, women took 11.0 ± 3.9 seconds and men 13.9 ± 3.4 seconds to conclude the test, with a 41% prevalence of dynapenia. In bivariate association analyses, longer chair test time was positively associated with aging (rho = 0.272, p = 0.012), worse physical function by HAQ (r = 0.362, p = 0.001), and inflammation by CRP (r = 0.306, p = 0.008). Worse lung function and mRSS were negatively associated with longer chair test times (rho = -0.278, p = 0.016; r = -0.256, p = 0.018). In multivariable analysis, aging, worse pulmonary function, and poorer physical function were dependent risk factors for dynapenia, with lower limb muscle strength estimated using the following equation: Chair stand = 9.128 + 0.115 × age - 0.063 × DLCOc + 1.200 × HAQ Conclusion: In our population of patients with systemic sclerosis, the prevalence of dynapenia was high (41%), particularly among older individuals with worse DLCOc and HAQ. REFERENCES: 1 Lima, Tatiana R L et al. "Lower limb muscle strength is associated with functional performance and quality of life in patients with systemic sclerosis." Brazilian journal of physical therapy vol. 19,2 (2015): 129-36. doi:10.1590/bjpt-rbf.2014.0084 2 Jochem C, Leitzmann M, Volaklis K, Aune D, Strasser B. Association Between Muscular Strength and Mortality in Clinical Populations: A Systematic Review and Meta-Analysis. J Am Med Dir Assoc. 2019;20(10):1213-1223. doi:10.1016/j.jamda.2019.05.015 Acknowledgements: Fundo de Incentivo à Pesquisa e Eventos (FIPE) do Hospital de Clínicas de Porto Alegre; and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). Disclosure of Interests: None declared.