title: Increased hip fracture and mortality in chronic kidney disease individuals: the importance of competing risks.
abstract: BACKGROUND
  Many studies have shown a correlation between chronic kidney disease (CKD) and fracture. However, increased mortality in CKD patients is a competing risk scenario not accounted for in previous studies. Our aim was to investigate the true impact of CKD on hip fracture after accounting for a competing risk with death.
  
  
  METHODS
  We conducted a population-based cohort study to determine the impact of CKD on hip fractures in individuals aged ≥50years old registered in the SIDIAP(Q) database (representative of 1.9 million people in Catalonia, Spain). Cox regression was used to estimate hazard ratio (HR) for death and hip fracture according to CKD status. A competing risk (Fine and Gray) model was fitted to estimate sub-HR for hip fracture in CKD or CKD-free patients accounting for differential mortality.
  
  
  RESULTS
  A total of 873,073 (32,934 (3.8%) CKD) patients were observed for 3 years. During follow-up, 4,823 (14.6%) CKD and 36,328 (4.3%) CKD-free participants died (HR, 1.83 [95% CI, 1.78-1.89]), whilst 522 (1.59%) and 6,292 (0.75%) sustained hip fractures, respectively. Adjusted Cox models showed a significantly increased risk of hip fractures for the CKD group (HR, 1.16 [1.06-1.27]), but this association was attenuated in competing risk models accounting for mortality (SHR, 1.14 [1.03-1.27]).
  
  
  CONCLUSIONS
  Both death and hip fracture rates are increased (by 83% and 16%, respectively) in CKD patients. However, the association between CKD and hip fractures is attenuated when an excess of mortality is taken into account. A competing risk with death must be considered in future analyses of association between CKD and any health outcomes.
authors.affiliation: Department of Nephrology, Hospital del Mar, Barcelona, Spain.
authors.forename: María José
authors.initials: MJ
authors.lastname: Pérez-Sáez
authors.affiliation: Institut Mar d'Investigacions Mediques, Barcelona, Spain; Idiap Jordi Gol Primary Care Research Institute, Universitat Autonoma de Barcelona, Barcelona, Spain; Musculoskeletal Epidemiology Unit, Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Oxford, UK. Electronic address: daniel.prietoalhambra@ndorms.ox.ac.uk.
authors.forename: Daniel
authors.initials: D
authors.lastname: Prieto-Alhambra
authors.affiliation: Department of Nephrology, Hospital del Mar, Barcelona, Spain.
authors.forename: Clara
authors.initials: C
authors.lastname: Barrios
authors.affiliation: Department of Nephrology, Hospital del Mar, Barcelona, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Crespo
authors.affiliation: Department of Nephrology, Hospital del Mar, Barcelona, Spain.
authors.forename: Dolores
authors.initials: D
authors.lastname: Redondo
authors.affiliation: Department of Internal Medicine, Hospital del Mar, Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Nogués
authors.affiliation: Idiap Jordi Gol Primary Care Research Institute, Universitat Autonoma de Barcelona, Barcelona, Spain; Department of Internal Medicine, Hospital del Mar, Barcelona, Spain.
authors.forename: Adolfo
authors.initials: A
authors.lastname: Díez-Pérez
authors.affiliation: Department of Nephrology, Hospital del Mar, Barcelona, Spain; Idiap Jordi Gol Primary Care Research Institute, Universitat Autonoma de Barcelona, Barcelona, Spain.
authors.forename: Julio
authors.initials: J
authors.lastname: Pascual
mesh_terms: D000368:Aged; D015331:Cohort Studies; D005260:Female; D006620:Hip Fractures / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D051436:Renal Insufficiency, Chronic / Q000150:complications* / Q000401:mortality*; D012307:Risk Factors
keywords: Bone disease; Chronic kidney disease; Epidemiology; Fractures; Mortality