Background:Geriatric hip fractures are common and associated with high morbidity and mortality. This study aimed to evaluate the incidence, timing, and risk factors of contralateral hip fracture after initial hip fracture.Methods:Initial hip fractures in patients older than 65 years were abstracted from the national, administrative M91Ortho PearlDiver data set. Incidence and timing of contralateral hip fractures in the following 10 years were identified. Kaplan-Meier survival analysis until contralateral hip fracture was conducted. To account for patient mortality over the later years, 2-year univariate and multivariate analyses were used to determine factors predictive of contralateral hip fracture.Results:Of the initial 104,311 hip fractures identified, contralateral hip fracture in the 10 years that followed was identified for 7,186 (6.9%), of which 68.4% occurred in the first 2 years. Kaplan-Meier survival analysis until contralateral fracture revealed the 10-year incidence to be 12.9% when controlling for those lost from the data set during the study period. Multivariate logistic regression revealed independent predictors of contralateral hip fracture in the 2 years after index hip fracture, when the incidence was greatest, to be female sex (odds ratio [OR] 1.15), body mass index < 20 (OR 1.30), and percutaneous pinning surgery for initial hip fracture fixation (OR 1.58) (P< 0.0001 for each).Conclusions:In a national cohort of 104,311 geriatric hip fractures, Kaplan-Meier analysis for contralateral hip fracture found the 10-year incidence to be 12.9%, of which nearly 70% were in the first 2 years, and predisposing factors were defined. As such, future research should aim to identify the cause and mitigate the risk of secondary contralateral hip fractures in geriatric patients.