title: It is premature to test older drivers with the SIMARD-MD.
abstract: BACKGROUND
  A new tool, the SIMARD-MD, has been proposed to help physicians identify cognitively impaired drivers who may be unfit to drive, but little empirical evidence is available to justify its use. We analyzed data from a cohort of older Canadian drivers who had undergone cognitive testing to: (1) correlate the SIMARD-MD with other tools that measure cognition (e.g., trail-making test), (2) identify how many drivers, using published cut-offs on the SIMARD-MD, would be recommended to lose their license, or be considered fit to drive, or be required to undergo further driving assessment, and (3) determine if the SIMARD-MD is biased by level of education as many cognitive tools are.
  
  
  METHODS
  Cross-sectional data from 841 drivers aged 70 and over from seven Canadian sites who are enrolled in a 5-year cohort study were used for the analyses. Scores on the SIMARD-MD were correlated with scores on the other cognitive measures. The recommendations that would be made based on the SIMARD-MD scores were based on published cut-off values suggested by the authors of the tool. The impact of education status was examined using linear regression controlling for age.
  
  
  RESULTS
  Correlations between the SIMARD-MD and other cognitive measures ranged from .15 to .86. Using published cut-off scores, 21 participants (2.5%) would have been recommended to relinquish their licenses, 428 (50.9%) would have been deemed fit to drive, and 392 (46.6%) would have been required to undergo further testing. We found a difference of 8.19 points (95% CI=4.99, 11.40, p<.001) in favor of drivers with post-secondary education versus those without, representing over 11% of the mean score.
  
  
  CONCLUSIONS
  The SIMARD-MD is unlikely to be valuable to clinicians because it lacks sufficient precision to provide clear recommendations about fitness-to-drive. Recommendations based solely on the SIMARD-MD may place many seniors at risk of losing their transportation mobility or incurring unnecessary stress and costs to prove they are safe to drive. Furthermore, the education bias may create an unwanted structural inequity. Hence, adoption of the SIMARD-MD as a tool to determine fitness-to-drive appears premature.
authors.affiliation: Centre for Research on Safe Driving, Lakehead University, Thunder Bay, Ontario, Canada; St. Joseph's Care Group, Thunder Bay, Ontario, Canada; Northern Ontario School of Medicine, Thunder Bay, Ontario, Canada. Electronic address: mbedard@lakeheadu.ca.
authors.forename: Michel
authors.initials: M
authors.lastname: Bédard
authors.forename: Shawn
authors.initials: S
authors.lastname: Marshall
authors.forename: Malcolm
authors.initials: M
authors.lastname: Man-Son-Hing
authors.forename: Bruce
authors.initials: B
authors.lastname: Weaver
authors.forename: Isabelle
authors.initials: I
authors.lastname: Gélinas
authors.forename: Nicol
authors.initials: N
authors.lastname: Korner-Bitensky
authors.forename: Barbara
authors.initials: B
authors.lastname: Mazer
authors.forename: Gary
authors.initials: G
authors.lastname: Naglie
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Porter
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Rapoport
authors.forename: Holly
authors.initials: H
authors.lastname: Tuokko
authors.forename: Brenda
authors.initials: B
authors.lastname: Vrkljan
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control*; D000368:Aged; D000369:Aged, 80 and over; D001334:Automobile Driving / Q000592:standards*; D002170:Canada; D003072:Cognition Disorders / Q000175:diagnosis*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008004:Licensure / Q000592:standards; D016014:Linear Models; D008297:Male; D008403:Mass Screening / Q000295:instrumentation; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D011594:Psychometrics / Q000295:instrumentation
keywords: Candrive; Knowledge translation; Older drivers; Screening