Sarcopenia as a prognostic marker in inflammatory bowel disease: Implications for endoscopic outcomes and loss of response to biologic therapy-A systematic review with narrative synthesis.

BACKGROUND: Sarcopenia and related body-composition abnormalities are increasingly discussed as potential prognostic markers in inflammatory bowel disease (IBD). Their relevance to endoscopic outcomes and biologic therapy-related outcomes remains insufficiently clarified because of heterogeneous definitions, study populations, and outcome measures. This systematic review investigated whether sarcopenia is associated with endoscopic outcomes and the course of biologic therapy in IBD, with particular attention to Crohn's disease. METHODS: In this PROSPERO-registered systematic review, PubMed and Embase were searched to April 1, 2025 for observational studies in adults with IBD assessing sarcopenia or muscle-related parameters and relevant clinical outcomes. RESULTS: Sarcopenia prevalence varied widely. Three studies assessed endoscopic outcomes, and five studies assessed biologic therapy-related outcomes, predominantly in Crohn's disease. Several studies reported associations between sarcopenia or low skeletal muscle parameters and poorer endoscopic outcomes, postoperative endoscopic recurrence, loss of response to biologic therapy, or reduced treatment persistence. Findings were not fully consistent, and interpretation was limited by heterogeneous sarcopenia definitions, different imaging modalities, small study numbers, and nonequivalent outcome measures. CONCLUSIONS: Sarcopenia and related body-composition parameters may be associated with an unfavorable endoscopic course and less favorable biologic therapy-related outcomes, particularly in Crohn's disease. However, the current evidence is predominantly observational, heterogeneous, and limited by small study numbers. Importantly, these associations do not establish causality, and sarcopenia may reflect greater inflammatory burden, malnutrition, or more severe disease rather than acting as an independent prognostic factor. These findings should therefore be considered hypothesis-generating and do not yet support routine implementation of sarcopenia assessment for risk stratification or treatment decision-making in IBD.