title: Comparison of methods for renal risk prediction in patients with type 2 diabetes (ZODIAC-36).
abstract: BACKGROUND
  Patients with diabetes are at high risk of death prior to reaching end-stage renal disease, but most models predicting the risk of kidney disease do not take this competing risk into account. We aimed to compare the performance of Cox regression and competing risk models for prediction of early- and late-stage renal complications in type 2 diabetes.
  
  
  METHODS
  Patients with type 2 diabetes participating in the observational ZODIAC study were included. Prediction models for (micro)albuminuria and 50% increase in serum creatinine (SCr) were developed using Cox regression and competing risk analyses. Model performance was assessed by discrimination and calibration.
  
  
  RESULTS
  During a total follow-up period of 10 years, 183 out of 640 patients (28.6%) with normoalbuminuria developed (micro)albuminuria, and 22 patients (3.4%) died without developing (micro)albuminuria (i.e. experienced the competing event). Seventy-nine out of 1,143 patients (6.9%) reached the renal end point of 50% increase in SCr, while 219 (19.2%) died without developing the renal end point. Performance of the Cox and competing risk models predicting (micro)albuminuria was similar and differences in predicted risks were small. However, the Cox model increasingly overestimated the risk of increase in SCr in presence of a substantial number of competing events, while the performance of the competing risk model was quite good.
  
  
  CONCLUSIONS
  In this study, we demonstrated that, in case of substantial numbers of competing events, it is important to account for the competing risk of death in renal risk prediction in patients with type 2 diabetes.
authors.affiliation: Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Ineke J
authors.initials: IJ
authors.lastname: Riphagen
authors.affiliation: Diabetes Centre, Isala Clinics, Zwolle, The Netherlands; Langerhans Medical Research Group, Zwolle, The Netherlands; Department of Internal Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Nanne
authors.initials: N
authors.lastname: Kleefstra
authors.affiliation: Diabetes Centre, Isala Clinics, Zwolle, The Netherlands.
authors.forename: Iefke
authors.initials: I
authors.lastname: Drion
authors.affiliation: Diabetes Centre, Isala Clinics, Zwolle, The Netherlands.
authors.forename: Alaa
authors.initials: A
authors.lastname: Alkhalaf
authors.affiliation: Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Merel
authors.initials: M
authors.lastname: van Diepen
authors.affiliation: Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Qi
authors.initials: Q
authors.lastname: Cao
authors.affiliation: Diabetes Centre, Isala Clinics, Zwolle, The Netherlands; Department of General Practice, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Klaas H
authors.initials: KH
authors.lastname: Groenier
authors.affiliation: Diabetes Centre, Isala Clinics, Zwolle, The Netherlands.
authors.forename: Gijs W D
authors.initials: GW
authors.lastname: Landman
authors.affiliation: Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Gerjan
authors.initials: G
authors.lastname: Navis
authors.affiliation: Diabetes Centre, Isala Clinics, Zwolle, The Netherlands; Department of Internal Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Henk J G
authors.initials: HJ
authors.lastname: Bilo
authors.affiliation: Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Stephan J L
authors.initials: SJ
authors.lastname: Bakker
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000652:urine; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D003928:Diabetic Nephropathies / Q000097:blood / Q000175:diagnosis* / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models
chemical_list: D015415:Biomarkers