Prediction of Chronic Fracture Pain in Patients with Osteoporotic Fractures Using the Japanese Short-form Central Sensitization Inventory: A Single-center Retrospective Observational Study in a Convalescent Rehabilitation Ward.

Objectives: Chronic fracture pain (CFP) is a significant issue in patients with osteoporotic fractures (OFs) in convalescent rehabilitation wards (CRWs). This study aimed to examine the association between CFP and the Japanese short-form Central Sensitization Inventory (CSI-9) and verify the predictive validity of CSI-9 in patients with OF admitted to a CRW.

Methods: This single-center retrospective study included 71 patients with OF (median age: 85.3 years, 54 females). CFP was defined as pain of Numerical Rating Scale (NRS) score ≥4 persisting at discharge, despite >3 months post-fracture. Multiple logistic regression and receiver operating characteristic curve analyses were performed to assess the association and predictive validity of the CSI-9 for CFP.

Results: The incidence of CFP was 38.0%. CSI-9 was independently associated with CFP at admission (odds ratio = 1.12, 95% confidence interval [CI]: 1.01-1.24) and discharge (odds ratio = 1.15, 95% CI: 1.03-1.29). The area under the curve for the CSI-9 was 0.727 (95% CI: 0.605-0.850) at admission and 0.752 (95% CI: 0.637-0.867) at discharge, indicating fair predictive accuracy. The optimal cutoff values for the CSI-9 were 8 points at admission and 6 points at discharge.

Conclusions: CSI-9 was independently associated with CFP and demonstrated moderate predictive accuracy in patients with OF in CRWs. Assessing central sensitization-related symptoms using the CSI-9 may be useful for evaluating and preventing CFP in this population. Further validation using large-scale prospective studies is required.