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P757 Visceral adiposity and not subcutaneous adiposity or body mass index is more strongly associated with relapse in inflammatory bowel disease

Tan, J.(1)*;Shadbolt, B.(2);Jain, T.(3);Subramaniam, K.(1);

(1)The Canberra Hospital, Department of Gastroenterology and Hepatology, Canberra, Australia;(2)Australian National University College of Science, Biological Data Science Institute, Canberra, Australia;(3)The Canberra Hospital, Radiology Department, Canberra, Australia;

Background

The role of body composition in inflammatory bowel disease (IBD) has still not been established due to heterogenous evidence. This study aimed to assess if abdominal body composition parameters were associated with outcomes in inflammatory bowel disease.

Methods

In this retrospective study abdominal body composition was evaluated using routinely acquired computed tomography (CT) from eligible patients with IBD between January 2014 and September 2021. Cross sectional areas of total fat (TFA), subcutaneous fat (SFA), visceral fat (VFA) and skeletal muscle (SMA) including their indices and ratios were measured at lumbar 3 (L3) vertebrae level using appropriate software. The outcome measure was relapse defined as acute flaring of symptoms and/or worsening biochemical markers, endoscopic recurrence requiring dose intensification of current therapy and surgical resection. Spearman’s correlations between body composition parameters were analysed. Binary logistic regression adjusting for demographics, smoking, disease characteristics (type, duration, location, behaviour) and medications was used to test for the relative significance of SFA, VFA, SMA and body mass index (BMI) on the outcome measures. A forward logarithmic likelihood method was used to test for it.

Results

Fifty-three IBD patients (58% male; 42% female) with 22 (42%) in relapse were included for abdominal CT analysis. Mean age of patients with relapse was 41.8 ± 16.2 years while those without relapse was 48.4 ± 12.5 years (p = 0.360). Mean BMI of patients with relapse was 25.6 ± 4.4 while those without relapse was 28.1 ± 7.0 (p = 0.457). Mean disease duration of patients with relapse was 15.3 ± 9.2 years while those without relapse was 21.3 ± 10.7 years (p = 0.583) [see Table 1]. Mean VFA was not significantly lower in relapse than remission (mean: 95.3 ± 99.5 cm² vs 119.7 ± 89.6 cm²; logarithmic p = 0.222), whereas mean SFA was significantly higher in relapse than remission (mean: 129.0 ± 64.3 cm² vs 225.3 ± 156.8 cm²; logarithmic p = 0.016) [see Table 2]. VFA and BMI correlated strongly with all other body composition parameters according to Spearman’s model (p < 0.001) [see Table 3]. After performing binary logistic regression and accounting for variables including age, gender, smoking status, type of IBD, disease characteristics (duration, location, behaviour), corticosteroid use, biologic therapy, anti-TNF level, VFA (p = 0.013) was significantly associated with relapse in comparison to SFA (p = 0.063) and BMI (p = 0.563).




Conclusion

Visceral adiposity and not BMI or subcutaneous adiposity is more strongly associated with relapse in IBD.