Bill, an eighty-two-year-old patient whom you’ve been seeing for years comes into your clinic one afternoon. It’s been a few years since he was diagnosed with Parkinson’s, and his health has been consistently declining. You decide that now is the time to advise Bill to stop driving. Before you do so, Bill’s wife tells you that Bill loves driving, and for him driving is a symbol of his freedom and control over his life. You worry about the effect your warning will have. Will he even stop driving? Will he resent you for the warning? Will this have a negative impact on his mental health? In this week’s issue of NEJM, a Special Article from Redelmeier et al. attempts to determine the effects of physician warnings to patients unfit to drive.
From 2006 to 2009 the authors followed 100,075 patients from Ontario who received a medical warning to stop driving from 6,098 physicians. Each patient served as their own control, and the total number of crashes in the three-year period prior to the warning (during the baseline interval) was compared to the number of crashes in the one-year interval following the warning. A road crash was defined as any time the patient had an emergency room visit due to a road crash in which they were the driver. The authors also separately counted the number of crashes in which the patients were pedestrians or passengers.
During the baseline interval, the patients experienced 4.8 events per 1,000 individuals each year. In the one-year after the warning, the patients accounted for 2.7 road crashes per 1,000 individuals, a 45% relative reduction in risk (p < 0.001). This reduction in the number of crashes was consistent across all demographic subgroups and among patients with different characteristics. Emergency room visits as pedestrians or passengers in car crashes did not change significantly after the physician’s warning. Although there was a significant reduction in the number of crashes experienced in which these patients were drivers, the rate of crashes after the warning was still higher than the population average (1.98 events per 1,000 drivers). While the rate did not return to the rate of crashes in the general public, the decrease observed indicates that the physician’s warning did have some impact on the patient, potentially by causing them to stop driving, encouraging them to be more safe when they did drive, or inspiring family members to urge them not to drive. In any case, we can see that warnings from a physician can lead to fewer crashes.
But there are also negative consequences. Emergency room visits due to depression increased from 19.2 per 1,000 patients annually to 23.9 events per 1,000 patients annually after the warning. Although this may be a result of their disease progression and not the warning, it still indicates that there may be some negative consequence on the patient’s mental well being when patients are told not to drive.
It can often be hard to know the impact of our statements to patients. This study shows that it’s important to give these warnings when necessary, but given the negative consequences, physicians should be careful only to give them when they are essential. Now that you know, when you give Bill the warning you might try to address the negative effects that your advice may have on his outlook.
Have you seen similar negative consequences of warnings that you’ve given to patients who are unfit to drive? Now that we are aware of these potential consequences, how can we address and avoid them while still successfully delivering warnings not to drive?