Physician warnings to potentially unfit drivers may reduce road crashes, according to a New England Journal of Medicine study.

Researchers examined data on patients in Ontario, Canada, where beginning in 2006, physicians were offered a financial incentive to warn medically unfit patients against driving. From 2006 through 2009, over 100,000 patients received warnings.

The annual rate of crashes in which the patient was the driver and presented to the emergency department decreased from 4.76 events per 1000 people in the period before warnings to 2.73 per 1000 in the year afterward. This reduction was significant, although the post-warning crash rate remained above the rate in the general population. Patients with dementia, stroke, depression, fainting, or epilepsy saw the greatest reductions; all age groups benefited.

In the post-warning period, return visits to physicians decreased and ED visits for depression increased — suggesting that such warnings, while injury-preventing, may “exacerbate mood disorders and compromise the doctor-patient relationship,” the authors note.

Source: NEJM