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

Byline: Cathleen Colon-Emeric (1,5), Maragatha Kuchibhatla (1), Carl Pieper (1), William Hawkes (2), Lisa Fredman (3), Jay Magaziner (2), Sheryl Zimmerman (4), Kenneth W. Lyles (1,5) Keywords: Aged; Epidemiology; Hip fracture Abstract: 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. Author Affiliation: (1) Center for the Study of Aging and Human Development, Department of Biometry and Bioinformatics, Duke University Medical Center, Box 3003, Durham, NC 27710, USA (2) Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA (3) Department of Epidemiology and Biostatistics, Boston University School of Public Health, Boston, Massachusetts, USA (4) Cecil G. Sheps Center for Health Services Research, University of North Carolina, Chapel Hill, North Carolina, USA (5) Geriatrics Research Education and Clinical Center, Durham VA Medical Center, Durham, North Carolina, USA Article History: Received Date: 14/11/2002 Accepted Date: 14/05/2003 Online Date: 03/10/2003