Харитонова Александра Олеговна

Background: In patients with inflammatory bowel diseases (IBD), skeletal muscle involvement includes not only reduced muscle mass but also decreased muscle strength (dynapenia). Previous studies in IBD have mainly focused on quantitative assessment of muscle area by computed tomography (CT), while reduced muscle strength has been studied separately from CT characteristics. It remains unclear whether dynapenia in IBD patients is primarily associated with decreased skeletal muscle area or with changes in muscle quality, including reduced muscle density and myosteatosis. Aim: To evaluate the association between handgrip strength and CT-derived skeletal muscle parameters in patients with IBD. Methods: A single-center cross-sectional study was conducted, including patients with IBD aged 18–75 years hospitalized from January to April 2026 at the Department of Gastroenterology of University Clinical Hospital No. 1 of I. M. Sechenov First Moscow State Medical University. All participants underwent abdominal CT during hospitalization. Muscle strength was assessed by handgrip dynamometry; dynapenia was defined according to the European Working Group on Sarcopenia in Older People (EWGSOP2) criteria. Skeletal muscle area, skeletal muscle index (SMI), and CT-derived muscle density were calculated from abdominal CT images using a convolutional neural network-based artificial intelligence algorithm Comp2Comp. Association analysis was performed using multivariable linear regression adjusted for sex, age, and body mass index. Results: The study included 53 IBD patients, of whom 32 (60%) were male; median age was 38 [28; 51] years. Crohn’s disease was diagnosed in 24 (45%) patients, ulcerative colitis in 29 (55%). Dynapenia was identified in 7 (13%) of 53 patients. In multivariable regression analysis, no statistically significant association was found between handgrip strength and SMI (β = 0.29 kg per 1 cm²/m²; p = 0.182). At the same time, a positive association was observed between handgrip strength and CT-derived muscle density (β = 0.44 kg per 1 HU; 95% confidence interval 0.002–0.87; p = 0.048). Conclusion: In IBD patients, dynapenia is associated with lower muscle density and is not related to SMI. These findings demonstrate the potential of using CT-derived qualitative skeletal muscle characteristics in IBD to identify patients with reduced functional muscle properties.