Obesity, Sarcopenia and Myosteatosis: Impact on Clinical Outcomes in the Operative Management of Crohn’s Disease

Background: Obesity, sarcopenia, and myosteatosis in inflammatory bowel disease may confer negative outcomes, but their prevalence and impact among patients with Crohn's disease (CD) have not been systematically studied. The aim of this study was to assess nutritional status and body composition among patients undergoing resectional surgery for CD and determine impact on operative outcomes. Methods: Consecutive patients with CD undergoing resection from 2000 to 2018 were studied. Total, subcutaneous, and visceral fat areas and lean tissue area (LTA) and intramuscular adipose tissue (IMAT) were determined preoperatively by computed tomography at L3 using SliceOmatic (Tomovision, Canada). Univariable and multivariable linear, logistic, and Cox proportional hazards regression were performed. Results: One hundred twenty-four consecutive patients were studied (ileocolonic disease 53%, n = 62, biologic therapy 34.4% n = 43). Mean fat mass was 22.7 kg, with visceral obesity evident in 23.9% (n = 27). Increased fat stores were associated with reduced risk of emergency presentation but increased corticosteroid use (β 9.09, standard error 3.49; P = .011). Mean LBM was 9.9 kg. Sarcopenia and myosteatosis were associated with impaired baseline nutritional markers. Myosteatosis markers IMAT (P = .002) and muscle attenuation (P = .0003) were associated with increased grade of complication. On multivariable analysis, IMAT was independently associated with increased postoperative morbidity (odds ratio [OR], 1.08; 95% confidence interval (CI), 1.01-1.16; P = .037) and comprehensive complications index (P = .029). Measures of adiposity were not associated with overall morbidity; however, increased visceral fat area independently predicted venous thromboembolism (OR, 1.02; 95% CI, 1.00-1.05; P = .028), and TFA was associated with increased wound infection (OR, 1.00; 95% CI, 1.00-1.01; P = .042) on multivariable analysis. Conclusion: Myosteatosis is associated with nutritional impairment and predicts increased overall postoperative morbidity following resection for CD. Despite its association with specific increased postoperative risks, increased adiposity does not increase overall morbidity, reflecting preservation of nutritional status and relatively more quiescent disease phenotype. Impaired muscle mass and function represent an appealing target for patient optimization to improve outcomes in the surgical management of CD. Keywords: Crohn’s disease; body composition; comprehensive complications index; computed tomography; fat mass; inflammatory bowel disease; lean body mass; nutrition; obesity; sarcopenia; subcutaneous fat; visceral fat.