Efficacy of Osteoporosis Treatment in Nonagenarians With Proximal Femoral Fractures: A Retrospective Cohort Study.

Introduction We aimed to retrospectively evaluate the effectiveness of osteoporosis treatment in patients aged ≥90 years with proximal femoral fractures, with a focus on secondary fracture prevention. Methods This retrospective cohort study included 247 nonagenarians (mean age: 93.5 years) who underwent surgery for proximal femoral fractures at our hospital between 2017 and 2022. Patients were categorized into three groups: those for whom new treatment was initiated after the fracture, those who had pre-existing treatment before the fracture, and those without treatment. The primary outcome was the incidence of secondary fractures during an average follow-up of 4.4 years. Stratified comparisons were conducted across treatment groups. Multivariable adjustment was considered, but not ultimately performed due to model instability. Results The incidence of secondary fractures was significantly lower in the pre-existing treatment group (7/64 (11%)) than in the new treatment (15/50 (30%)) and non-treatment (38/133 (29%)) groups (p = 0.009). The rate of regaining ambulatory function was also higher in the treatment groups (new: 29/40 (72.5%), pre-existing: 37/54 (68.5%)) compared with the non-treatment group (45/103 (43.7%)) (p = 0.0007). Unadjusted comparisons indicated that newly initiated treatment did not reduce secondary fracture risk, whereas pre-existing treatment was associated with a lower incidence. Conclusions Pre-existing osteoporosis treatment significantly reduced secondary fracture risk and improved functional recovery in our cohort of nonagenarians. Initiating treatment after fracture did not provide similar benefits, possibly due to delayed therapeutic onset. Our results suggest that early and continuous osteoporosis management is essential, even in very elderly populations, to improve outcomes and reduce future fracture burden.