Background: Osteoporotic vertebral fractures are common fragility fractures in older adults and are associated with increased mortality. However, prognostic factors among patients managed conservatively remain insufficiently characterized. This study aimed to identify independent predictors of mortality in patients with osteoporotic vertebral fractures treated without surgery.

Methods: We retrospectively analyzed 596 consecutive patients with osteoporotic vertebral fractures who were treated conservatively at a regional hospital between 2016 and 2024. Repeated admissions were excluded so that only the first eligible fracture per patient was included. Baseline variables included age, sex, body mass index, and prognostic nutritional index, which reflects nutritional and immune status. Multivariable Cox proportional hazards regression analysis was performed to identify independent predictors of mortality. Time-dependent receiver operating characteristic analysis using inverse probability weighting was conducted to determine optimal cut-off values.

Results: During follow-up, 122 patients (20.5%) died. Patients who died were older, more frequently male, and had lower body mass index and prognostic nutritional index. Multivariable analysis identified older age, male sex, lower body mass index, lower prognostic nutritional index, and collagen vascular disease as independent predictors of mortality (all p < 0.05). The optimal cut-off values for predicting 5-year mortality were 17.8 kilograms per square meter for body mass index and 38.3 for prognostic nutritional index. Patients below these thresholds showed significantly worse survival.

Conclusions: Mortality following conservatively treated osteoporotic vertebral fractures is substantial. Simple clinical parameters, including body mass index and prognostic nutritional index, may facilitate early risk stratification and support targeted multidisciplinary management in high-risk patients.