title: Development and evaluation of a composite risk score to predict kidney transplant failure.
abstract: BACKGROUND
  Although risk factors for kidney transplant failure are well described, prognostic risk scores to estimate risk in prevalent transplant recipients are limited.
  
  
  METHODS
  Development and validation of risk-prediction instruments.
  
  
  METHODS
  The development data set included 2,763 prevalent patients more than 12 months posttransplant enrolled into the LOTESS (Long Term Efficacy and Safety Surveillance) Study. The validation data set included 731 patients who underwent transplant at a single UK center.
  
  
  METHODS
  Estimated glomerular filtration rate (eGFR) and other risk factors were evaluated using Cox regression.
  
  
  RESULTS
  Scores for death-censored and overall transplant failure were based on the summed hazard ratios for baseline predictor variables. Predictive performance was assessed using calibration (Hosmer-Lemeshow statistic), discrimination (C statistic), and clinical reclassification (net reclassification improvement) compared with eGFR alone.
  
  
  RESULTS
  In the development data set, 196 patients died and another 225 experienced transplant failure. eGFR, recipient age, race, serum urea and albumin levels, declining eGFR, and prior acute rejection predicted death-censored transplant failure. eGFR, recipient age, sex, serum urea and albumin levels, and declining eGFR predicted overall transplant failure. In the validation data set, 44 patients died and another 101 experienced transplant failure. The weighted scores comprising these variables showed adequate discrimination and calibration for death-censored (C statistic, 0.83; 95% CI, 0.75-0.91; Hosmer-Lemeshow χ(2)P = 0.8) and overall (C statistic, 0.70; 95% CI, 0.64-0.77; Hosmer-Lemeshow χ(2)P = 0.5) transplant failure. However, the scores failed to reclassify risk compared with eGFR alone (net reclassification improvements of 7.6% [95% CI, -0.2 to 13.4; P = 0.09] and 4.3% [95% CI, -2.7 to 11.8; P = 0.3] for death-censored and overall transplant failure, respectively).
  
  
  CONCLUSIONS
  Retrospective analysis of predominantly cyclosporine-treated patients; limited study size and categorization of variables may limit power to detect effect.
  
  
  CONCLUSIONS
  Although the scores performed well regarding discrimination and calibration, clinically relevant risk reclassification over eGFR alone was not evident, emphasizing the stringent requirements for such scores. Further studies are required to develop and refine this process.
authors.affiliation: Renal Institute of Birmingham, University Hospital Birmingham, Edgbaston, Birmingham, UK.
authors.forename: Jason
authors.initials: J
authors.lastname: Moore
authors.forename: Xiang
authors.initials: X
authors.lastname: He
authors.forename: Shazia
authors.initials: S
authors.lastname: Shabir
authors.forename: Rajesh
authors.initials: R
authors.lastname: Hanvesakul
authors.forename: David
authors.initials: D
authors.lastname: Benavente
authors.forename: Paul
authors.initials: P
authors.lastname: Cockwell
authors.forename: Mark A
authors.initials: MA
authors.lastname: Little
authors.forename: Simon
authors.initials: S
authors.lastname: Ball
authors.forename: Nicholas
authors.initials: N
authors.lastname: Inston
authors.forename: Atholl
authors.initials: A
authors.lastname: Johnston
authors.forename: Richard
authors.initials: R
authors.lastname: Borrows
mesh_terms: D000328:Adult; D015331:Cohort Studies; D016208:Databases, Factual / Q000592:standards; D005260:Female; D005500:Follow-Up Studies; D006084:Graft Rejection / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D006801:Humans; D016030:Kidney Transplantation / Q000276:immunology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012107:Research Design / Q000592:standards*; D012307:Risk Factors