title: Contralateral hip fractures and other osteoporosis-related fractures in hip fracture patients: incidence and risk factors. An observational cohort study of 1,229 patients.
abstract: OBJECTIVE
  To report risk factors, 1-year and overall risk for a contralateral hip and other osteoporosis-related fractures in a hip fracture population.
  
  
  METHODS
  An observational study on 1,229 consecutive patients of 50 years and older, who sustained a hip fracture between January 2005 and June 2009. Fractures were scored retrospectively for 2005-2008 and prospectively for 2008-2009. Rates of a contralateral hip and other osteoporosis-related fractures were compared between patients with and without a history of a fracture. Previous fractures, gender, age and ASA classification were analysed as possible risk factors.
  
  
  RESULTS
  The absolute risk for a contralateral hip fracture was 13.8 %, for one or more osteoporosis-related fracture(s) 28.6 %. First-, second- and third-year risk for a second hip fracture was 2, 1 and 0 %. Median (IQR) interval between both hip fractures was 18.5 (26.6) months. One-year incidence of other fractures was 6 %. Only age was a risk factor for a contralateral hip fracture, hazard ratio (HR) 1.02 (1.006-1.042, p = 0.008). Patients with a history of a fracture (33.1 %) did not have a higher incidence of fractures during follow-up (16.7 %) than patients without fractures in their history (14 %). HR for a contralateral hip fracture for the fracture versus the non-fracture group was 1.29 (0.75-2.23, p = 0.360).
  
  
  CONCLUSIONS
  The absolute risk of a contralateral hip fracture after a hip fracture is 13.8 %, the 1-year risk was 2 %, with a short interval between the 2 hip fractures. Age was a risk factor for sustaining a contralateral hip fracture; a fracture in history was not.
authors.affiliation: Department of Orthopaedics, Reinier de Graaf Group, PO box 5011, 2600 GA, Delft, The Netherlands. ajhvochteloo@hotmail.com
authors.forename: Anne J H
authors.initials: AJ
authors.lastname: Vochteloo
authors.forename: Boudewijn L S
authors.initials: BL
authors.lastname: Borger van der Burg
authors.forename: Maarten A
authors.initials: MA
authors.lastname: Röling
authors.forename: Diederik H
authors.initials: DH
authors.lastname: van Leeuwen
authors.forename: Peter
authors.initials: P
authors.lastname: van den Berg
authors.forename: Arthur H P
authors.initials: AH
authors.lastname: Niggebrugge
authors.forename: Mark R
authors.initials: MR
authors.lastname: de Vries
authors.forename: Wim E
authors.initials: WE
authors.lastname: Tuinebreijer
authors.forename: Rolf M
authors.initials: RM
authors.lastname: Bloem
authors.forename: Rob G H H
authors.initials: RG
authors.lastname: Nelissen
authors.forename: Peter
authors.initials: P
authors.lastname: Pilot
mesh_terms: D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006620:Hip Fractures / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D058866:Osteoporotic Fractures / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors