Predicting the Subsequent Contralateral Hip Fracture: Is FRAX the Answer?

Abstract

To (1) determine the ability of the Fracture Risk Assessment Tool (FRAX) to identify the probability of contralateral hip fractures within 2 years of index fracture and (2) identify independent risk factors for a subsequent hip fracture. Retrospective. Urban, academic medical center. This study included a consecutive series of patients treated for unilateral hip fractures between September 2015 and July 2019. Eight hundred thirty-two consecutive patients were included in the analysis with a mean age of 81.2 ± 9.9 years. Thirty-one (3.7%) patients sustained a contralateral hip fracture within 2 years with these patients sustaining the second fracture at a mean 294.1 days ± 197.7 days. The average FRAX score for the entire cohort was 11.9 ± 7.4, and the area under receiving operating characteristic curve (AUROC) for FRAX score was 0.682 (95% CI, 0.596-0.767). Patients in the high-risk FRAX group had a >7% risk of contralateral hip fracture within 2 years. Independent risk factors for contralateral hip fracture risk included patient age 80 years or older and decreasing BMI. This study demonstrates the strong ability of the FRAX score to triage patients at risk of subsequent contralateral hip fracture within 2 years. In this high-risk FRAX group, patients age older than 80 years and who have decreasing BMI after their index fracture have a 12.5% increased risk of fracture within 2 years which is 4× higher than the current World Health Organization 10-year 3% hip fracture risk standard used to initiate pharmacologic treatment. Therefore, high-risk patients identified using this methodology should be targeted more aggressively with preventative measures including social, medical, and potentially surgical interventions. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.