Comorbidity in Drivers with Parkinson's Disease

The Impact of Advanced Age on Driving Safety in Adults with Medical Conditions

BACKGROUND

Adults aged 85 and older, often referred to as the oldest-old, are the fastest-growing segment of the population. The rapidly increasing number of older adults with chronic and multiple medical conditions poses challenges regarding their driving safety.

OBJECTIVE

To investigate the effect of advanced age on driving safety in drivers with medical conditions.

METHODS

We categorized 3,425 drivers with preexisting medical conditions into four age groups: middle-aged (55-64 years, n = 1,386), young-old (65-74 years, n = 1,013), old-old (75-84 years, n = 803), or oldest-old (85 years and older, n = 223). All underwent a formal driving evaluation. The outcome measures included fitness to drive recommendation by the referring physician, comprehensive fitness to drive decision from an official driving evaluation center, history of motor vehicle crashes (MVCs), and history of traffic violations.

RESULTS

The oldest-old reported more cardiopulmonary and visual conditions, but less neurological conditions than the old-old. Compared to the middle-aged, the oldest-old were more likely to be considered unfit to drive by the referring physicians (odds ratio [OR] = 4.47, 95% confidence interval [CI] 2.20-9.10) and by the official driving evaluation center (OR = 2.74, 95% CI 1.87-4.03). The oldest-old reported more MVCs (OR = 2.79, 95% CI 1.88-4.12) compared to the middle-aged.

CONCLUSION

Advanced age adversely affected driving safety outcomes. The oldest-old are a unique age group with medical conditions known to interfere with safe driving. Driving safety strategies should particularly target the oldest-old since they are the fastest-growing group and their increased frailty is associated with severe or fatal injuries due to MVCs.

Comparison of Unsafe Driving Across Medical Conditions

OBJECTIVE

To compare risks of unsafe driving in patients with medical conditions.

METHODS

This large population-based study included all patients who were referred for a fitness-to-drive evaluation at an official driving evaluation center in 2013 and 2014. Risks of unsafe driving included physician's fitness-to-drive recommendation, comprehensive fitness-to-drive decision, motor vehicle crash history, and traffic violation history.

RESULTS

A total of 6584 patients were included in the study. Risks of unsafe driving were significantly different across medical conditions (P<.001 for all outcome measures). Patients with neurological conditions comprised the majority of the database (4837; 74%), but were not at the highest risk for unsafe driving. Patients with psychiatric conditions or substance abuse did worse on most driving safety outcomes, despite their low representation in the total sample (359 [6%] and 46 [1%], respectively).

CONCLUSION

The risk of unsafe driving varied greatly across medical conditions. Sensitization campaigns, education, and medical guidelines for physicians and driver licensing authorities are warranted to identify patients at risk, especially for those with psychiatric conditions and substance abuse problems.