Research Papers

Determining the validity of the AMA guidelines: A retrospective analysis of the ADReS and rate of crash in older drivers

Filename FINAL-PAPER-95.doc
Filesize 309 KB
Version 1
Date added June 10, 2012
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Category 2012 CMRSC XXII Banff
Tags Session 2A
Author Andrew Woolnough, Danish Salim, Malcolm Man-Son-Hing, Michelle M. Porter, Kelly Weegar, Mark J. Rapoport, Shawn Marshal


Purpose: As a result of the aging population, the number of older persons holding a drivers license has increased. Chronic health conditions associated with aging can lead to changes in driving ability. The Canadian Driving Research Initiative for Vehicular Safety in the Elderly (Candrive) is a CIHR-funded 5-year, prospective study aiming to develop an in-office screening tool that will help clinicians identify potentially at risk older drivers. Currently, no tools exist to directly predict crash risk in this population. However, the American Medical Association (AMA) has designed opinion-based guidelines to screen for older driver fitness. Specifically, the AMA recommends that physicians use the Assessment of Driving Related Skills (ADReS) as a test battery to measure vision, cognition and motor/somatosenory functions related to driving. This functional assessment consists of a visual acuity test (Snellen E chart), visual fields by confrontation test, trail-making test part B, clock drawing test, rapid pace walk, manual test of range of motion and motor strength. The following study aimed to use the baseline data from the Candrive common cohort of older drivers to evaluate the validity of ADReS subtests currently used to assess functional ability in older adults. Specifically, we hypothesized that the ADReS subtest scores would be associated with a history of crashes in the 2 years prior to baseline assessment.

Methods: Participants (n=928, aged 70 or older) were recruited from 7 Canadian cities and completed a comprehensive clinical assessment at initiation of the study between April 2009 and November 2010. The assessment included all tests selected as part of the ADReS. Retrospective crash data were obtained from participants' jurisdictions for all sites, for crashes within 2-years preceding the baseline assessments. An analysis was performed to investigate the association between the results of the ADReS tests and the motor vehicle crash rate. Significance was tested using the Pearson's Chi-Square test and T-test.

Results: Data obtained from provincial databases indicated that 60 of the 928 participants (6.5%) were involved in a motor vehicle collision within the 2 year time period preceding the baseline assessment. Contrary to what was expected from AMA guidelines, there were no statistically significant associations between abnormal performance on the individual tests comprising the ADReS (vision, cognition and motor/somatosensory) and history of crash among Candrive participants (p>0.05).

Conclusions: Although limitations are inherent in a retrospective analysis, abnormalities on the subtests comprising the ADReS were not associated with a history of crash. This suggests the need for more sensitive tools to properly assess crash risk of older drivers, for prospective analyses of risk over time, and for an evidence base to support influential clinical practice guidelines.

Andrew Woolnough, Danish Salim, Malcolm Man-Son-Hing, Michelle M. Porter, Kelly Weegar, Mark J. Rapoport, Shawn Marshal