Clinical Risk Factors for Recurrent Fracture after Hip Fracture: A Prospective Study

Additional fractures after hip fracture are common, but little is known about the risk factors associated with these events. We determined the clinical risk factors associated with fracture following a low-trauma hip fracture and whether clinical risk factors for subsequent fracture were modified by zoledronic acid (ZOL). In this post hoc analysis of the HORIZON Recurrent Fracture trial, 2,127 men and women were randomized within 90 days of surgical hip fracture repair to receive intravenous ZOL 5 mg yearly or placebo. All patients received a loading dose of vitamin D and daily oral calcium and vitamin D supplements. In the multivariable model age, sex, BMI, femoral neck T score, and one or more fall risk factors were significant predictors of subsequent fracture. Race, history of prior fracture other than the index hip fracture, T score < −2.5 as a dichotomous variable, and type of index hip fracture were not associated with a different risk of subsequent fractures. Treatment with ZOL did not modify the impact of these risk factors. Well-established risk factors for fracture risk such as age, sex, BMI, and fall risk factors will also contribute to fracture risk in patients who have already suffered a hip fracture, while other prior fractures and T score < −2.5 are not predictive of subsequent fractures. Baseline risk factors in hip fracture patients were predictive of fracture in both ZOL- and placebo-treated participants, and there is no difference in the risk of subsequent fractures based on index hip fracture type.