title: Overestimation of prostate cancer mortality and other-cause mortality by the Kaplan-Meier method.
abstract: BACKGROUND
  To assess the extent of overestimation of the cumulative probability of death by the Kaplan-Meier method with the competing-risks regression analysis as reference approach.
  
  
  METHODS
  Data were derived from the screening arm of the Rotterdam branch of the European Randomized Study of Screening for Prostate Cancer (ERSPC). The screening arm consisted of 21210 men between the ages of 55 and 74 at study entry. Follow up concerning mortality was complete through 2008. Endpoints were 5 and 10 year cumulative probabilities of prostate cancer death and death from other causes. Relative bias was defined as the ratio of the cumulative probability of death as determined by the Kaplan-Meier method, relative to the cumulative probability obtained by the competing-risks analysis.
  
  
  RESULTS
  According to the Kaplan-Meier method, the 5 year cumulative probability of death from prostate cancer was 0.0101, compared with 0.0099 according to the competing-risk analysis [1.8% overestimation]. At 10 year, these numbers were 0.0347 and 0.0321, respectively [8.0% overestimation]. For death from other causes, the cumulative probabilities at 5 year were 0.0399 and 0.0397 according to the Kaplan-Meier and the competing-risks method [0.6% overestimation], respectively. At 10 year, the probabilities were 0.141 and 0.139 [1.7% overestimation], respectively.
  
  
  CONCLUSIONS
  When competing events are present, the competing-risks regression analysis is to be preferred over the Kaplan-Meier method in the estimation of the cumulative probability of the event of interest.
authors.affiliation: Department of Urology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Xiaoye
authors.initials: X
authors.lastname: Zhu
authors.forename: Ries
authors.initials: R
authors.lastname: Kranse
authors.forename: Meelan
authors.initials: M
authors.lastname: Bul
authors.forename: Chris H
authors.initials: CH
authors.lastname: Bangma
authors.forename: Fritz H
authors.initials: FH
authors.lastname: Schröder
authors.forename: Monique J
authors.initials: MJ
authors.lastname: Roobol
mesh_terms: D000368:Aged; D002423:Cause of Death; D005060:Europe; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009026:Mortality; D011471:Prostatic Neoplasms / Q000401:mortality*; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors