title: Functional status and readmissions in unilateral hip fractures.
abstract: OBJECTIVE
  To test whether functional status is a robust predictor of acute care readmission risk in patients who have been discharged to an inpatient rehabilitation facility (IRF) following a unilateral hip fracture.
  
  
  METHODS
  Retrospective database study using a large administrative data set.
  
  
  METHODS
  A retrospective analysis of data from the Uniform Data System for Medical Rehabilitation from the years 2002 to 2011 was performed, examining patients with an impairment of unilateral hip fracture. A basic prediction model based on functional status was compared with competing models incorporating medical comorbidities. C statistics were compared to evaluate model performance.
  
  
  RESULTS
  There were a total of 433,154 patients: 32,783 (7.87%) patients were transferred back to an acute hospital, including 7937 (1.91%) transferred within 3 days, 16,150 (3.88%) transferred within 7 days, and 32,607 (7.83%) transferred within 30 days after IRF admission. The C statistics for the Basic Model are 0.710, 0.674, and 0.667 at days 3, 7, and 30, respectively. Compared with the Basic Model, the best performing Basic-Plus model was the Basic+Elixhauser Model with C statistic differences of +0.013, +0.014, and +0.019, and the best performing Age-Comorbidity Model was the Age+Elixhauser Model with C statistic differences of -0.110, -0.079, and -0.065 at days 3, 7, and 30, respectively.
  
  
  CONCLUSIONS
  Functional status is a robust and potentially modifiable risk factor for patients admitted to IRFs following a unilateral hip fracture.
authors.affiliation: New England Rehabilitation Hospital of Portland, 335 Brighton Ave, Portland, ME 04102. E-mail: pbgerrard@gmail.com.
authors.forename: Paul
authors.initials: P
authors.lastname: Gerrard
authors.forename: Richard
authors.initials: R
authors.lastname: Goldstein
authors.forename: Margaret A
authors.initials: MA
authors.lastname: DiVita
authors.forename: Chloe
authors.initials: C
authors.lastname: Slocum
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Ryan
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Mix
authors.forename: Paulette
authors.initials: P
authors.lastname: Niewczyk
authors.forename: Lewis
authors.initials: L
authors.lastname: Kazis
authors.forename: Ross
authors.initials: R
authors.lastname: Zafonte
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Schneider
mesh_terms: D015897:Comorbidity; D004185:Disability Evaluation; D005260:Female; D006620:Hip Fractures / Q000534:rehabilitation*; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D010351:Patient Discharge / Q000706:statistics & numerical data*; D010359:Patient Readmission / Q000706:statistics & numerical data*; D010360:Patient Transfer / Q000706:statistics & numerical data; D012047:Rehabilitation Centers / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012307:Risk Factors