P818 Imaging-based preoperative body composition is associated with the risk of postoperative complications and postoperative endoscopic recurrence in patients with Crohn’s disease
Authors: Bak M , Demers K , van Ruler O , Pierik M J , van der Bilt J D W , Romberg-Camps M , Dijkstra G , Duijvestein M , van der Marel S , Maljaars P W J , Buskens C J , Bakers F C H , van Dijk D P J , Brecheisen R , Bongers B C , van Rossum E F C , de Witte D , Jansen S V , Jharap B J H , Horjus C S , van Schaik F D M , West R L , de Boer N K H , van der Woude C J , Stassen L P S , de Vries A C 
Published: January 2024

Abstract

Background
Alterations in body composition are common in Crohn’s disease (CD) patients and influence disease outcomes. However, the impact of preoperative body composition on postoperative outcomes is not completely understood. Therefore, this study aimed to investigate the association of preoperative body composition with postoperative complications and endoscopic recurrence in CD patients undergoing ileocolic (re-)resection (ICR).

Methods
CD patients (≥16 years) scheduled for an ICR with a computed tomography (CT) scan available (&lt;12 months prior to ICR) were identified from an ongoing prospective, multicenter cohort study. Skeletal muscle mass (SM), visceral (VAT) and subcutaneous adipose tissue (SAT), and their radiation attenuation (RA) were assessed on a single CT image at L3 using a validated deep-learning automatic segmentation tool (Mosamatic). Low RA is associated with increased tissue triglyceride content (e.g. myosteatosis in case of SM). Cut-offs, based on sex-specific tertiles, were set at the lower and upper tertile for low and high values. The primary outcome was the development of overall postoperative complications within 90 days. Secondary outcomes were postoperative endoscopic recurrence (Rutgeerts’ score ≥ i2b) at 6 months, infectious complications, and moderate to severe complications (Clavien-Dindo ≥ II). Multivariable logistic regression was performed to assess the association of body composition variables with postoperative outcomes, including adjustment for confounders.

Results
121 patients were included (median age 37.1 years (IQR 27.1–53.2), 59.5% female). Median disease duration at surgery was 3.6 years (IQR 0.4–12.7), and 57.0% had prior exposure to ≥ 1 biological. Overall postoperative complications were reported in 51.2%, endoscopic recurrence in 33.3%, infectious complications in 26.4%, and moderate to severe complications in 41.3%. High SM-RA (aOR 0.67; 95%CI 0.16–0.85) and low VAT (aOR 0.38; 95%CI 0.17–0.87) were associated with decreased overall postoperative complications. Low VAT-RA was associated with decreased endoscopic recurrence (aOR 0.21; 95%CI 0.07–0.67), and high SAT with increased infectious complications (aOR 3.05; 95%CI 1.28–7.28).

Conclusion
Low visceral adipose tissue and high radiation attenuation of skeletal muscle (i.e. no myosteatosis) were protective of overall postoperative complications in CD patients undergoing ICR. Low radiation attenuation of visceral adipose tissue (i.e. high triglyceride content) was protective of endoscopic recurrence. High subcutaneous adipose tissue increased the risk of postoperative infectious complications. Further research in larger populations is warranted to validate these findings to improve preoperative stratification and strategies for CD.