Impact of Osteoporosis Therapy in Geriatric Proximal Femur Fractures: A Retrospective Analysis from the German Registry for Geriatric Trauma (ATR-DGU®)

Background: Each year, hundreds of thousands of geriatric patients suffer proximal femur fractures, which often result in irreversible functional decline. Although anti-osteoporotic medications have been shown to reduce the incidence of fragility fractures, the effects of pharmacotherapy on fracture injury patterns, postoperative ambulatory capacity, and survival outcomes are not yet fully understood. Methods: We conducted a retrospective cohort study using the AltersTraumaRegister DGU ® (ATR-DGU), a multicenter prospective registry spanning 196 certified geriatric trauma centers in Germany, Austria, and Switzerland (2016 through 2024). We included patients aged 70 years or older with isolated, surgically treated proximal femur fractures and stratified them by documented use of osteoporosis medication before the index fracture (OM group) versus no pre-fracture therapy (no-OM group). Primary endpoints were mortality during the acute hospital stay and at 120-day follow-up, as well as walking ability—defined as any functional ambulation versus none—at 7 and 120 days postoperatively. The main secondary endpoint was fracture morphology. We fitted multivariable logistic and linear regression models adjusted for age, sex, ASA classification, and anticoagulation; walking-ability models were additionally adjusted for pre-fracture ambulatory status. Results: Of 70,386 patients (mean age, 84.4 years; 70.4% female), 15,771 (22.4%) were receiving osteoporosis medication prior to the index fracture. Patients in the OM group were frailer with worse ASA Scores (80.3% vs. 72.5% with an ASA ≥3) and lower ambulation (62.5% vs. 50.4% requiring at least two crutches or not able to ambulate out of the home environment). Patients in the OM group had a 19% higher chance of sustaining a trochanteric versus a femoral neck fracture than patients in the no-OM group (51.9% vs. 46.8%; adjusted odds ratio 1.19; 95% CI, 1.15 to 1.24; p < 0.001). Pre-existing therapy showed no association with mortality during the acute hospital stay (adjusted OR, 0.93; 95% CI, 0.86 to 1.01; p = 0.098) or with walking ability at 7 days (adjusted OR, 1.03; 95% CI, 0.98 to 1.09; p = 0.198). At the 120-day follow-up (n = 19,544 in the adjusted model follow-up cohort), slightly higher odds of death were observed in the frailer OM group (adjusted OR, 1.12; 95% CI, 1.01 to 1.25; p = 0.04), though the lower confidence bound approached unity. A trend toward improved ambulation was seen in the OM group at 120-day follow-up (adjusted OR, 1.11; 95% CI, 0.99 to 1.25; p = 0.074). Conclusions: Pre-existing osteoporosis therapy was associated with lower odds of femoral neck versus trochanteric fracture patterns. A trend toward improved ambulation accompanied a slightly increased risk of mortality in patients with pre-existing osteoporosis therapy at 120-day follow-up, although this must be weighed against substantial loss to follow-up and residual confounding. More research is needed to understand the effects of anti-osteoporosis medications on patients who do suffer hip fractures despite osteoporotic therapy.