The contribution of hip fracture to risk of subsequent fractures: data from two longitudinal studies.

BACKGROUND

The contribution of hip fracture to the risk of subsequent fractures is unclear.

METHODS

Data from the Baltimore Hip Studies and the Established Populations for Epidemiologic Studies of the Elderly (EPESE) were used. Baltimore subjects enrolled at the time of hip fracture ( n=549) and EPESE subjects without previous fractures at baseline ( n=10,680) were followed for 2-10 years. Self-reported nonhip skeletal fracture was the outcome, and hip fracture was a time-varying covariate in a survival analysis stratified by study site. The model was adjusted for race, sex, age, BMI, stroke, cancer, difficulty walking across a room, dependence in grooming, dependence in transferring, and cognitive impairment.

RESULTS

The rate of all subsequent self-reported fractures after hip fracture was 10.4 fractures/100 person-years. The unadjusted hazard of nonhip skeletal fracture was 2.52 (95% confidence interval 2.05 to 3.12) for subjects with hip fracture compared with subjects without; when adjusted for other known fracture risk factors the hazard ratio was 1.62 (1.30 to 2.02). Men and women had a similar relative risk increase. The increased risk of secondary fracture after hip fracture persisted over time.

CONCLUSIONS

A hip fracture is associated with a 2.5-fold increased risk of subsequent fracture, which is not entirely explained by prefracture risk factors. Careful attention to secondary prevention is warranted in these patients.