Prevalence and progression of hip osteoarthritis in individuals with diffuse idiopathic skeletal hyperostosis

Diffuse idiopathic skeletal hyperostosis (DISH) primarily affects the axial skeleton, but its association with hip osteoarthritis (OA) remains unclear. We investigated the prevalence and 5 year progression of hip OA in individuals with DISH and explored risk factors for progression.

This retrospective cohort study reviewed 694 asymptomatic individuals who underwent whole-body computed tomography (CT) for cancer screening (2016-2023) and had follow-up CT at ≥ 5 years. DISH was diagnosed using CT-based criteria. We identified 143 individuals with DISH and selected 143 age- and sex-matched controls without DISH (1:1). Hip OA was assessed using a CT-based composite score (0-14, bilateral). Radiographic hip OA was defined as a bilateral score ≥ 10, and progression as an increase of ≥ 2 points over 5 years. Multivariable regression analyses were performed to identify independent predictors of progression.

The DISH group had higher total hip OA scores and a higher prevalence of radiographic hip OA than controls at baseline and follow-up. However, OA progression rates did not differ significantly between groups. Among individuals with DISH, the number of ankylosed vertebral segments was independently associated with hip OA progression.

Individuals with DISH show a higher prevalence of radiographic hip OA. Extensive spinal ankylosis may increase the risk of hip OA progression, supporting the need for longitudinal monitoring of hip joint health in DISH.