Erosive hand osteoarthritis is associated with increased risk of incident osteoporotic fractures in post-menopausal women (QUALYOR cohort)

Erosive hand osteoarthritis (ErHOA) is a severe form of HOA associated with greater inflammation and disability. We aimed to explore its association with bone loss and fracture. The QUALYOR study is a prospective study of postmenopausal women ≥50 years followed for 14 years. At the 6-year visit (baseline), HOA was assessed using radiographs and the AUSCAN questionnaire. Osteoporotic (OP) status combined DXA and fracture history. Incident OP fractures were medically confirmed during follow-up. Age-standardized incident rates of OP fractures (SIR) were calculated (Poisson regression). Associations between baseline HOA and incident OP fractures were analysed using Cox models adjusted for key fracture risk factors. Linear mixed-effects models adjusted for age and BMI evaluated annual BMD changes according to HOA status. Exploratory path analysis was conducted. The analysis included 1180 women (mean age 71.7 ± 6.4 years, follow-up 4.6 ± 0.9 years): 364 (30.8%) had no HOA, 340 (28.8%) symptomatic HOA (SHOA), and 141 (11.9%) ErHOA. Overall, 131 women (11.1%) sustained 166 incident OP fractures (mean time to event 2.2 ± 1.4 years). SIR for first OP fracture were 58.5/1000PY (95%CI 16.6-155.7) in ErHOA vs 30.2/1000PY (95%CI 10.9-66.6) without HOA. HRs for first fracture were 1.9 (95%CI 1.09-3.3) in ErHOA compared to no HOA. The association was not observed for other HOA phenotypes. Exploratory path analysis suggested that the association persisted after accounting for bone loss over time. ErHOA is a strong independent predictor of osteoporotic fracture in postmenopausal women, warranting investigation of specific mechanisms involved.