High serum concentrations of growth differentiation factor-15 in male Crohn’s disease patients with low skeletal muscle index

Abstract Sarcopenia is defined as low skeletal muscle index (SMI) in addition to low muscle strength (MS) or low physical function, and many biomarkers have been reported. In Crohn's disease (CD), low SMI is associated with predictors and complications of intestinal resection. Therefore, in many reports of CD, sarcopenia was defined only by SMI. However, there have been no reports of MS in Japan. Our study aimed to investigate the frequency of sarcopenia by assessing both SMI and MS in Japanese patients with CD and biomarkers predicting low SMI. We evaluated SMI using bioelectrical impedance analysis, handgrip strength, and blood tests, including CRP, ALB, IL-6, TNFα, GDF-8, and GDF-15 as biomarker candidates for 78 CD patients in our hospital. Sarcopenia and low SMI were 8% and 42.3%, respectively. Each candidate biomarker and SMI were negatively correlated with GDF-15 (Pearson's r=-0.414, P = 0.0031) in males and positively correlated with ALB (r = 0.377, P = 0.048), and negatively correlated with IL-6 (r=-0.484, P = 0.012) in females. Multivariate analysis adjusted for these items, age, and BMI showed a significant difference in male GDF-15 (P = 0.011, OR: 7.86, 95% CI: 1.09–56.58). Therefore, GDF-15 in male patients is considered a biomarker of low SMI.