Friday, September 28, 2012

Docs Can Prevent Car Crashes Among Elderly

Docs Can Prevent Car Crashes Among Elderly

Physicians' warnings to patients that they are potentially unfit to drive can prevent car crashes, researchers reported.
The annual rate of car accidents among patients who were so warned fell about 45% in the year after the doctor's intervention, compared with the 3 years before, according to Donald Redelmeier, MD, of Sunnybrook Health Sciences Centre in Toronto, and colleagues in the Sept. 27 issue of the New England Journal of Medicine.
The "data suggest that practicing physicians may be able to help prevent serious trauma from road crashes," the authors concluded.
Redelmeier and colleagues noted that there was no significant change in the rate of accidents in which the patients were passengers or pedestrians. But there may have been psychological repercussions: emergency department visits for depression rose and patients saw their physicians less frequently after they were warned off driving.
The Canadian province of Ontario, the country's most populous, has some 9 million licensed drivers and in 2008 – the midpoint of the study – recorded 229,196 car accidents resulting in death, disability, or property damage.
Of those accidents, 17,929 required the driver to visit an emergency department, for an overall annual rate of about 1.98 events per 1,000 drivers.
Since 1968, the researchers noted, Ontario doctors have had the duty to report a driver who is unfit to operate a motor vehicle by reason of a condition such as alcoholism, dementia, sleep disorders, or depression without psychosis.
But few doctors followed through, Redelmeier and colleagues noted, so that in 2006 the province introduced a payment to doctors for the process. That change offered a chance to test the effectiveness of medical warnings in reducing accidents, they wrote.
Between April 1, 2006, and Dec. 31, 2009, the researchers identified 100,075 patients who got a medical warning from a total of 6,098 doctors. The study period included the first 4 years after the change to the medical warning program, as well as at least one year of follow-up for each patient.
Between 10% and 30% of warnings resulted in the patient having his or her license suspended, Redelmeier told MedPage Today in an email, but "not all suspended drivers stop driving."
The primary endpoint of the study was the change over time in the annual rate of accidents in which the patients were driving a vehicle and needed emergency hospital care.
So, for each patient in the cohort, the researchers looked for emergency room visits – before and after the warning -- with diagnostic codes for injuries that resulted from accidents in which the patient was the driver. Crashes in which the patient was a passenger or a pedestrian were excluded from the primary analysis.
In the 3 years before they were warned, patients who subsequently received a warning were the drivers in 1,430 car crashes that led to emergency care. That worked out to an annual rate of 4.76 such accidents per 1,000 people – more than twice the rate in the general population.
During the year after the warning, patients were the drivers in 273 crashes that led to an emergency department visit -- equivalent to an annual rate of 2.73 accidents per 1,000 persons, Redelmeier and colleagues reported.
Although the latter rate is still higher than what was seen in the general population, the observed decline was equivalent to a 45% relative reduction in the risk of accident (95% CI 36 to 52, P<0.001).
Analysis by subgroups found a similar reduction in risk regardless of demographics, physician characteristics, the timing and type of accident, or the severity of injuries.
The intervention had no effect on the yearly rate of emergency department visits for which the patient was a pedestrian -- 1.30 events per 1,000 patients before the warning and 1.29 afterward. There was also no effect on the rate of emergency department visits in which the patient was a passenger -- 3.08 events per 1,000 patients annually before the warning and 3.04 after.
On the other hand, Redelmeier and colleagues reported, emergency department visits for depression rose from 19.15 per 1,000 patients annually before the warning to 23.91 afterward – a 27% relative increase.
The warning may also have affected the doctor-patient relationship, the researchers suggested, since 29% of the warned patients saw their doctor less often afterward than they had before.
The study results should apply more widely than just Ontario, since six U.S. states, including California, Pennsylvania, and New Jersey, have similar regulations, Redelmeier told MedPage Today.
The study comes as a prominent Irish gerontologist, Desmond O'Neill, MD, of Dublin's Trinity College, argued in that mandatory medical screening of older drivers -- which has been imposed in some European countries and is proposed in the U.K. -- is unwarranted and has dangerous consequences, including an increased risk of older people being injured as pedestrians.
Age-related medical screening should be abolished, he argued, adding that "this must not imply professional neglect of medical fitness to drive among older drivers."
Redelmeier commented that "such medical determinations are not easy."
"That's why medical judgment is needed and why an effective policy must not be taken to excess," he added.
The study was supported by the Canada Research Chairs program, the Canadian Institutes of Health Research, and the University of Toronto Faculty of Medicine. The researchers did not report any financial links with industry.
O'Neill did not report any external support for his article or any potential conflicts.

Primary source: New England Journal of Medicine
Source reference:
Redelmeier DA, et al "Physicians' warnings for unfit drivers and the risk of trauma from road crashes" N Engl J Med 2012; 367: 1228-1236.
Additional source: BMJ
Source reference:


Michael Smith
North American Correspondent
North American Correspondent for MedPage Today, is a three-time winner of the Science and Society Journalism Award of the Canadian Science Writers√Ę€™ Association. After working for newspapers in several parts of Canada, he was the science writer for the Toronto Star before becoming a freelancer in 1994. His byline has appeared in New Scientist, Science, the Globe and Mail, United Press International, Toronto Life, Canadian Business, the Toronto Star, Marketing Computers, and many others. He is based in Toronto, and when not transforming dense science into compelling prose he can usually be found sailing.

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