Crohn's and bones: assessing bone microarchitecture using high-resolution peripheral quantitative computed tomography

Crohn's disease (CD) is known to negatively affect BMD and inflammatory (non-stricture) and stricturing CD are the two common phenotypes. Studies exploring CD phenotypes with advanced imaging techniques, such as HR-pQCT, are lacking. Therefore, the aim of this cross-sectional study was to examine differences in bone quality, including volumetric BMD, bone microarchitecture, bone geometry, estimated bone strength, and void spaces, between inflammatory and stricturing CD phenotypes using HR-pQCT. Participants aged 55 yr and over were recruited and scanned by HR-pQCT (XtremeCT II) at the distal radius and tibia. Finite element analysis estimated bone strength and void space analysis captured structural inhomogeneities in the trabecular compartment. Health history and CD-specific information were assessed with blood work and questionaries. Two-way ANOVA, with sex as a factor, compared CD phenotypes. Sixty-one participants were recruited (52% female, mean age: 65.3 ± 6.1 yr). Group-by-sex interactions were observed at the tibia. Specifically, males in the stricturing group exhibited a smaller cortical bone area than males in the inflammation group, while no differences were detected between groups for females (p = .038). Similarly, males in the stricturing group had lower cortical thickness than males in the inflammatory group, with no differences between groups for females (p = 0.033). At both the radius and tibia, there were group interactions for bone microarchitecture parameters where the stricturing group had compromised bone microarchitecture compared with the inflammatory group. No differences were observed for bone strength or fracture rate between groups. Using HR-pQCT, we observed differences in bone microarchitecture and geometry between individuals with inflammatory and stricturing CD phenotypes. Future research should be prospective and should consider CD phenotype and sex when assessing skeletal health and fracture risk in this population.