title: Vascular disease, ESRD, and death: interpreting competing risk analyses.
abstract: OBJECTIVE
  Vascular disease, a common condition in CKD, is a risk factor for mortality and ESRD. Optimal patient care requires accurate estimation and ordering of these competing risks.
  
  
  METHODS
  This is a prospective cohort study of screened (n=885) and randomized participants (n=837) in the Modification of Diet in Renal Disease study (original study enrollment, 1989-1992), evaluating the association of vascular disease with ESRD and pre-ESRD mortality using standard survival analysis and competing risk regression.
  
  
  RESULTS
  The method of analysis resulted in markedly different estimates. Cumulative incidence by standard analysis (censoring at the competing event) implied that, with vascular disease, the 15-year incidence was 66% and 51% for ESRD and pre-ESRD death, respectively. A more accurate representation of absolute risk was estimated with competing risk regression: 15-year incidence was 54% and 29% for ESRD and pre-ESRD death, respectively. For the association of vascular disease with pre-ESRD death, estimates of relative risk by the two methods were similar (standard survival analysis adjusted hazard ratio, 1.63; 95% confidence interval, 1.20-2.20; competing risk regression adjusted subhazard ratio, 1.57; 95% confidence interval, 1.15-2.14). In contrast, the hazard and subhazard ratios differed substantially for other associations, such as GFR and pre-ESRD mortality.
  
  
  CONCLUSIONS
  When competing events exist, absolute risk is better estimated using competing risk regression, but etiologic associations by this method must be carefully interpreted. The presence of vascular disease in CKD decreases the likelihood of survival to ESRD, independent of age and other risk factors.
authors.affiliation: Departments of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA. mgrams2@jhmi.edu
authors.forename: Morgan E
authors.initials: ME
authors.lastname: Grams
authors.forename: Josef
authors.initials: J
authors.lastname: Coresh
authors.forename: Dorry L
authors.initials: DL
authors.lastname: Segev
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Kucirka
authors.forename: Hocine
authors.initials: H
authors.lastname: Tighiouart
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Sarnak
mesh_terms: D000367:Age Factors; D015897:Comorbidity; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000401:mortality* / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D014652:Vascular Diseases / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy