title: Apparent and internal validity of a Monte Carlo-Markov model for cardiovascular disease in a cohort follow-up study.
abstract: OBJECTIVE
  To determine the apparent and internal validity of the Rotterdam Ischemic heart disease & Stroke Computer (RISC) model, a Monte Carlo-Markov model, designed to evaluate the impact of cardiovascular disease (CVD) risk factors and their modification on life expectancy (LE) and cardiovascular disease-free LE (DFLE) in a general population (hereinafter, these will be referred to together as (DF)LE).
  
  
  METHODS
  The model is based on data from the Rotterdam Study, a cohort follow-up study of 6871 subjects aged 55 years and older who visited the research center for risk factor assessment at baseline (1990-1993) and completed a follow-up visit 7 years later (original cohort). The transition probabilities and risk factor trends used in the RISC model were based on data from 3501 subjects (the study cohort). To validate the RISC model, the number of simulated CVD events during 7 years' follow-up were compared with the observed number of events in the study cohort and the original cohort, respectively, and simulated (DF)LEs were compared with the (DF)LEs calculated from multistate life tables.
  
  
  RESULTS
  Both in the study cohort and in the original cohort, the simulated distribution of CVD events was consistent with the observed number of events (CVD deaths: 7.1% v. 6.6% and 7.4% v. 7.6%, respectively; non-CVD deaths: 11.2% v. 11.5% and 12.9% v. 13.0%, respectively). The distribution of (DF)LEs estimated with the RISC model consistently encompassed the (DF)LEs calculated with multistate life tables.
  
  
  CONCLUSIONS
  The simulated events and (DF)LE estimates from the RISC model are consistent with observed data from a cohort follow-up study.
authors.affiliation: Department of Epidemiology and Biostatistics, Erasmus Medical Center, Rotterdam, the Netherlands.
authors.forename: Rogier L
authors.initials: RL
authors.lastname: Nijhuis
authors.forename: Theo
authors.initials: T
authors.lastname: Stijnen
authors.forename: Anna
authors.initials: A
authors.lastname: Peeters
authors.forename: Jacqueline C M
authors.initials: JC
authors.lastname: Witteman
authors.forename: Albert
authors.initials: A
authors.lastname: Hofman
authors.forename: M G Myriam
authors.initials: MG
authors.lastname: Hunink
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000401:mortality; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008017:Life Expectancy; D008297:Male; D008875:Middle Aged; D009010:Monte Carlo Method; D009426:Netherlands / Q000453:epidemiology; D012307:Risk Factors