Body Composition Changes and Related Factors in Patients with Ulcerative Colitis: A Retrospective Single-Center Study in China.

BACKGROUND This study retrospectively explored body composition changes and related factors in patients with ulcerative colitis (UC). MATERIAL AND METHODS Patients with UC and healthy individuals who served as the healthy control at the Affiliated Hospital of Qingdao University September 2017 to August 2018 were retrospectively analyzed. Clinical data and laboratory examination indexes were collected. The skeletal muscle area (SMA) of the third lumbar vertebra cross-section, the subcutaneous fat area (SFA), and the visceral fat area (VFA) at the umbilical level were measured by computed tomography (CT), and the skeletal muscle index (SMI) was calculated to evaluate the loss of muscle mass. RESULTS Data from a total of 80 patients (median age, 49.49 years; 44 [55%] men) with active UC in the UC group and 80 healthy people age- and sex-matched in the healthy control group were collected. The incidence of low SMI and malnutrition was remarkably higher in the UC group than in the healthy control group (P<0.05). Low SMI was observed in 62.5% of UC patients who had a normal body mass index. Based on classification by the Truelove and Witts' criteria, the prevalence of malnutrition in severe UC patients was remarkably higher than that in mild and moderate UC patients (P<0.05). Based on the disease extent, the prevalence of low SMI in E3 type UC was dramatically higher than that in E2 type (P=0.028). CONCLUSIONS Loss of muscle mass was related to disease extent in patients with UC. Loss of muscle mass is more likely to be associated with malnutrition.