Risk factors for a second nonsimultaneous hip fracture in a prospective cohort study

Introduction The risk factors for a second nonsimultaneous hip fracture are unclear, and in general, it is empirically assumed that they are similar to those associated with the first hip fracture. We aimed to determine the incidence of a second hip fracture and define the characteristics of the patients sustaining the event in a prospective cohort study in a Spanish population. Materials and methods We conducted a multicentric, prospective cohort study in a representative sample of 45 hospitals from 15 autonomic regions in Spain. In total, the study included 994 patients. One hundred and one patients presented a nonsimultaneous contralateral hip fracture, constituting the intervention group. The remaining 893 patients presenting with a hip fracture formed the control group. The main outcome measures of this study were sociodemographic characteristics of the patient, comorbid conditions, and baseline and postfracture clinical outcomes (inpatient complications and acute mortality). Results The key fracture risk factors were a history of fragility fractures, the need for assistance when walking outdoors and a history of falls. There were no associations between the groups in any of the common fragility risk factors, including rheumatoid arthritis, secondary osteoporosis, or steroid consumption. The results showed that patients suffering a nonsimultaneous hip fracture had an increased risk of mortality after discharge compared with the control group. Conclusion A nonsimultaneous second hip fracture leads to a near-significant increase in four-month mortality. In our study, this fracture was associated with a history of falls, prior fragility fractures, and the need for a walking aid.