Recorded fracture liaison service plus discharge zoledronic acid prescription and 730-day refracture risk after surgically treated vertebral fracture in older adults: a target-trial-informed discharge landmark analysis

BackgroundHospitalization for vertebral fracture offers an opportunity to connect acute care with secondary fracture prevention. We examined whether recorded fracture liaison service (FLS) use plus a positive discharge zoledronic acid (ZOL) prescription/dispensing field was associated with lower postdischarge refracture risk.MethodsUsing a public fracture registry from Kunshan, China, we included patients aged 65 years or older admitted between 2019 and 2021 with a surgically treated thoracic or lumbar vertebral fracture. Eligible patients were alive and refracture-free at discharge, with discharge defining the landmark time zero. We compared recorded FLS plus a positive discharge ZOL prescription (pathway) against neither a recorded FLS nor a discharge ZOL/alendronate (comparator). Fifty-fold multiple imputation and ridge propensity score overlap weighting addressed missing measured covariates and group differences. Weighted Aalen–Johansen estimation treated death as a competing event. Confidence intervals (CIs) were derived from 1,000 patient-level bootstrap replicates.ResultsThe cohort included 585 patients (266 pathway; 319 comparator), with 37 refractures and 26 deaths before refracture. The maximum weighted absolute standardized mean difference was 0.046 for fitted propensity terms and 0.087 for the common clinical panel across imputations. Estimated 730-day refracture risks were 2.40% (95% CI, 0.76%–4.31%) and 7.02% (95% CI, 4.12%–10.29%), respectively. The risk difference was −4.63 (95% CI, −8.38 to −1.24) percentage points and the risk ratio was 0.34 (95% CI, 0.10–0.76). Reduced and alternative propensity specifications yielded similar associations, although some left greater residual imbalance. The extended 2019–2022 analysis (n = 770) at 365 days was less conclusive [risk difference, −1.24 (95% CI, −3.62 to 1.07) percentage points].ConclusionsAmong older surgically treated vertebral fracture inpatients, recorded FLS plus positive discharge ZOL prescription was associated with lower estimated 730-day refracture incidence. This pathway-level observational association does not establish the independent effects of FLS or ZOL or confirm drug administration. Limited events and unmeasured treatment selection factors warrant cautious interpretation.