Please note: In 2003, the CTF updated its Grades of Recommendations to include an "I Recommendation" for situations where insufficient evidence exists to allow a recommendation to be made. (Formerly, these situations were captured under a "C Recommendation".) This change is not retroactive, and all "C Recommendations" made prior to 2003 have not been reevaluated in light of the new "I" recommendation grade. For a discussion of these recommendation grades, please link to the 2003 article in the Canadian Medical Association Journal here.
Burden of Suffering
Of the ten industrialized western countries Canada has the fourth highest
injury mortality rate (37.5/100,000) and the sixth highest motor vehicle
accident (MVA) fatality rate (15.8/100,000). The rate for males is consistently
almost twice that of females. Motor vehicles crashes are the leading cause
of death in persons aged 5 - 24; in 1986 they accounted for 38% of all
deaths in young persons aged 15-24.
High Risk Behaviours
High risk behaviours include seatbelt and alcohol use. The rate of
seat belt use among those persons fatally injured was considerably less
than among those with non-fatal or no injuries from MVAs. Alcohol intoxication
accounts for about 40% of persons killed in motor vehicle crashes. Studies
have consistently shown that fatally injured drivers are more likely to
have a blood alcohol level of at least 0.10% than are drivers who are not
killed.
Medical Impairment
Impaired vision, impaired hearing, decreased flexibility and dexterity,
and slowing of information processing capability result in abnormally high
accident rates in the elderly when exposure is taken into account. Less
than 0.5% of all deaths of elderly people are the result of road accidents,
but elderly drivers are over represented in low velocity, property-damage-only
collisions. Whether drivers with concomitant medical conditions have excessive
motor vehicle accidents is less clear.
Off Road Vehicles
Most injuries associated with all-terrain vehicles (ATVs) occur when
the driver loses control, the vehicle falls over, the driver is thrown
from the vehicle, or the vehicle collides with fixed objects such as fences
or trees. The 1987 data for numbers of vehicles in use and mortality, without
reference to patterns of vehicle use, yielded annual death rates of 1.7/1000
for 3-wheeled and 1.2/1000 for 4-wheeled ATVs. Canadian and U.S. studies
have revealed the following risk factors: excessive speed, improper apparel
and non-use of helmets, inexperience, and alcohol abuse.
Options
Primary options were legislation and physician counselling about occupant
protection systems (lap and shoulder belts, airbags, child safety seats,
safety helmets) and health behaviours (driving while intoxicated, use of
seat belts, infant safety seats). Monitoring of patients for medical impairment
was also considered.
Outcomes
Outcomes included crash mortality; injuries (moderate-to-serious, head,
non-crash); severity of injuries; hospital admission; hospital charges;
and use of occupant restraints.
Evidence
A MEDLINE search from 1981 to 1991 using the MeSH headings motor vehicle,
accident prevention and primary care physician yielded 151 citations. As
well, the 1989 report of the U.S. Preventive Services Task Force was used
extensively. Study results were synthesized in table or graphic format
only.
Values
The 13-member Task Force of experts in family medicine, geriatric medicine,
pediatrics, psychiatry and epidemiology used an evidence-based method for
evaluating the effectiveness of preventive health care interventions. Recommendations
were not based on cost-effectiveness of options. Patient preferences were
not discussed.
Background papers providing critical appraisal of the evidence and tentative
recommendations prepared by the chapter author were pre-circulated to the
members. Evidence for this topic was presented and deliberated upon in
1- to 2-day meetings, 2 to 3 times per year from January 1993 to June 1993.
Consensus was reached on final recommendations.
Benefits, Harms, and Costs
Effectiveness of occupant restraint systems has been demonstrated in
laboratory experiments, postcrash injury comparisons and postcrash judgments regarding the probable effects of restraints. Estimates from non-randomized
controlled trials suggest that proper use of lap and shoulder restraints
decreased the risk for moderate-to-serious injury in front seat occupants
by 45% to 55% and decreased risk for mortality by 40% to 50%. Victims who
were brought to the hospital had less severe injuries, were less likely
to be admitted, and incurred lower hospital charges. Despite this, it is
estimated that 3-point seat belts are not worn by 25% of Canadians. The
overall safety benefit of a combination airbag system and lap-shoulder
belt has not yet been determined.
Evidence from non-randomized controlled trials suggests that persons who refrain from drinking and driving have a significantly reduced risk of injury or death from motor vehicle accidents.
Few studies exist on the effectiveness of physician counselling on seat belt use or drinking and driving behaviour. Studies examining the use of infant safety seats (before use was mandated by law) found significant short-term improvements immediately after newborns were discharged from hospital, and for the next few months.
Descriptive studies report an excess of motor vehicle accidents among persons with known concomitant medical conditions. For example, elderly persons with impaired vision or hearing, decreased flexibility and dexterity, or slowing of information processing capabilities have abnormally high accident rates.
Cohort analytic studies in regions where helmet use for motorcyclists
is mandated by law report a 30% reduction in mortality, and a 75% reduction
in head injuries.
Recommendations
Recommendation grade [A, B, C, D, E] and level of evidence
[I, II-1, II-2, II-3, III] are indicated after each recommendation. Citations
in support of individual recommendations are identified in the guideline
text.