Car accidents in drivers with Parkinson's disease or multiple sclerosis: A Swedish nationwide study

Parkinson's disease (PD) and multiple sclerosis (MS) can impair driving. However, we lack evidence on car accidents associated with these diseases. The aims of this study were to examine what types of car accident were associated with drivers with PD and MS, compared to individuals with ulcerative colitis (UC; the comparison group), and to evaluate the occurrence of car accidents in relation to years since diagnosis.

This retrospective nationwide, registry-based study included drivers involved in car accidents between 2010 and 2019, based on the Swedish Traffic Accident Data Acquisition database. Data on pre-existing diagnoses were retrieved retrospectively from the National Patient Registry. Data analyses included group comparisons, time-to-event analysis, and binary logistic regression.

In total, 1491 drivers, including 199 with PD, 385 with MS, and 907 with UC, were registered to have been involved in a car accident. The mean time from diagnosis to the car accident was 5.6 years for PD, 8.0 years for MS, and 9.4 years for UC. Time to car accident since diagnosis differed significantly (p < 0.001) among groups (adjusted for age). Drivers with PD had more than twice the odds of a single-car accident than drivers with MS or UC, but no differences were observed between MS and UC.

Drivers with PD were older and experienced the car accident within a shorter timeframe after disease diagnosis. Although several factors may cause a car accident, fitness to drive could be more thoroughly evaluated for patients with PD by physicians, even early after the diagnosis.