Assessment of body composition-related imaging parameters indicative of sarcopenia in Chinese patients with Crohn's disease: correlation with disease severity and biologic efficacy.

Objectives: To evaluate the prognostic value of body composition-related imaging parameters in assessing Crohn's disease (CD) severity and biological responses in Chinese patients.

Methods: We retrospectively analyzed electronic medical records and Computed tomography (CT) images from 117 CD patients, including 90 with sarcopenia and 27 without. We calculated subcutaneous fat area (SFA), visceral fat area, skeletal muscle area (SMA), mesenteric fat index (MFI), skeletal muscle index (SMI), and muscle attenuation (MA). CD Activity Index (CDAI) score and Simple Endoscopic Score for CD (SES-CD) were used to evaluate inflammation and biologic efficacy. Correlation and comparative analyses were performed to determine associations between imaging parameters and clinical data. Receiver operating characteristic curve analysis evaluated the predictive performance of combined body composition indicators.

Results: Sarcopenia was associated with higher CDAI scores and lower body mass index, albumin, and hemoglobin levels but was not associated with SES-CD or rates of clinical/endoscopic remission or response to biologic therapy. SMI was inversely correlated with CDAI score and SES-CD and positively correlated with albumin and hemoglobin. Endoscopy responders had higher SMA, MFI, SMI, and MA than non-responders. SES-CD improvement was positively correlated with MFI and MA and negatively correlated with SFA. The combined analysis of SMI, MFI, and MA yielded an area under the curve of 0.743 for predicting endoscopic response to biologic therapies in CD patients.

Conclusions: SMI may indicate CD severity, while MFI and MA could predict biologic response. Integrating multiple body composition parameters enhances treatment outcome evaluation, suggesting their potential utility in CD assessment.