Body composition and Crohn's disease behavior: Is adiposity the main game changer?

We investigated the association between body composition upon diagnosis and complicated phenotypes and time until surgery in patients with Crohn's disease (CD). We conducted a retrospective cohort study including patients with CD who had a computed tomography enterography or a magnetic resonance enterography performed ≤6 mo of diagnosis. Skeletal muscle and visceral and subcutaneous adipose tissue cross-sectional areas were determined with computed tomography or magnetic resonance images at the third lumbar vertebral level, processed with the sliceOmatic (TomoVison, Magog, QC, Canada) and ABACS plugin. We included 63 patients: 33 (52%) men, median age 35 y. Disease location (L) and behavior (B) according to the Montreal classification were L1 (ileal disease) = 28 (44%), L2 (colonic disease) = 13 (21%), L3(ileocolonic disease) = 18 (28%), L1 + L4 (ileal and isolated upper disease) = 1 (2%), L3 + L4 (ileocolonic and isolated upper disease) = 3 (5%), B1 (non-stricturing) = 39 (62%), B2 (stricturing) = 11 (17%), and B3 (penetrating)= 13 (21%); 20 (32%) patients had perianal disease. Visceral obesity was present in 12 (19%) patients and was associated with higher age of CD onset (median 60 versus 34 y; P = 0.002) and complicated disease behavior (B2 and B3) (66.7% versus 31.7%; P = 0.021). After adjusting for age and perianal disease, total adipose tissue was associated with a 4% increase in the odds of complicated behavior per 10 cm2 of total adipose tissue (odds ratio [OR] = 1.004; 95% confidence interval [CI], 1.00–1.008; P = 0.043). Median follow-up time was 3.35 y, during which 15 (24%) of patients underwent abdominal surgery. Visceral obesity was associated with 5.10-times higher risk of abdominal surgery (95% CI, 1.52–17.09; P = 0.008); after adjusting for disease behavior, visceral obesity maintained a near-significant association with a 2.90-times higher risk of surgery (95% CI, 0.83–10.08; P = 0.09). Total fat was associated with complicated disease phenotype and visceral obesity, with higher risk of abdominal surgery and shorter time until surgery.