Diferenças na composição e funcionalidade muscular: explorando os pontos anatômicos da tomografia computadorizada e os componentes do SARC-F

Abstract

Introduction: Body composition assessment is essential for determining nutritional status and identifying conditions such as sarcopenia, which is associated with unfavorable clinical and functional outcomes in cancer patients. The SARC-F is a tool that identifies signs suggestive of sarcopenia, allowing for faster and more effective interventions. However, the SARC-F has limitations in terms of its correlation, which tends to be stronger with muscle functionality than with muscle mass. The use of precise techniques, such as computed tomography (CT), offers a comprehensive assessment of muscle status, including morphological quantity and quality. In this context, exploring the relationship between SARC-F components and different muscle sites from CT scans may improve our understanding of the complex interaction between SARC-F and muscle health, with a particular focus on muscle functionality. Objectives: To investigate the differences between the SARC-F score and muscle parameters measured in the L3, thigh and gluteal regions of CT scans in relation to each SARC-F component/question. Methods: A secondary cross-sectional analysis of a cohort with prospective data collection was carried out. The study involved patients treated at the Onofre Lopes University Hospital (HUOL), of both sexes, hospitalized or in outpatient care, all diagnosed with cancer, aged 18 years or over, who underwent a CT scan within three months of the evaluation. The sample was selected for convenience and there was no sample size calculation. The study participants completed the SARC-F questionnaire at the time of the assessment. An overall SARC-F score ≥ 4 was considered to be suggestive of sarcopenia. Muscle assessment through CT measurements was carried out using single cross-sectional images at the level of the third lumbar vertebra (L3) in the abdominal region, in the thigh region and in the total gluteal region at the level of the second sacral vertebra. Skeletal muscle cross-sectional area (SMA), skeletal muscle index (SMI, normalized for height2) and skeletal muscle density (SMD) were assessed for all anatomical points (L3, thigh and gluteus). Results: A total of 128 patients were included in this analysis (53.1% women, 61.7% elderly). Patients with SARC-F ≥ 4 had significantly lower MDS values at all landmarks (L3, thigh and gluteus). There was a statistical trend (P < 0.10) towards lower SMI at L3 and both lower SM and SMI at the gluteal site. Patients who reported difficulties with strength, requiring assistance to walk and climbing stairs had significantly lower MDS values at L3 (P = 0.039; P = 0.033; P = 0.012, respectively). At gluteal and thigh level, only patients with difficulty climbing stairs (P = 0.012) had significantly lower SMD values. Only gluteal MSD was independently associated with the SARC-F score (adjusted β -0.09, 95% CI -0.16 to -0.02). Conclusion: The study revealed an independent association between the SARC-F score and muscle composition (MSD) at the gluteal level. Our results indicate that individuals with changes in muscle composition may show signs suggestive of sarcopenia and impaired muscle functionality