Chronic medical conditions and traffic safety: review of the California experience

Psychiatric and behavioral problems in aggressive drivers

Motor vehicle accidents (MVAs) are a leading cause of accidental death and injury, and aggressive driving has been identified as a risk factor for MVAs. Assessing psychiatric and behavioral disturbances in aggressive drivers is germane to the development of prevention and intervention programs for this population. The present study compared the prevalence of psychiatric diagnoses and behavioral problems in young adult drivers with self-reported high driving aggression to that of drivers with low driving aggression. Aggressive drivers evidenced a significantly higher current and lifetime prevalence of Oppositional Defiant Disorder, Alcohol and Substance Use Disorders, and Cluster B Personality Disorders, and a significantly greater lifetime prevalence of Conduct Disorder, Attention-Deficit/Hyperactivity Disorder, and Intermittent Explosive Disorder. Aggressive drivers also had a significantly greater prevalence of self-reported problems with anger, as well as a greater family history of anger problems and conflict. The findings suggest that prevention and intervention programs designed to reduce aggressive driving may need to address the presence of psychiatric and behavioral problems that could potentially complicate treatment or impede responses to treatment.

Pain and pain treatment were associated with traffic accident involvement in a cohort of middle-aged workers

BACKGROUND AND OBJECTIVE

To assess the influence of medical conditions on road traffic accidents among a cohort of middle-aged workers and pensioners.

STUDY DESIGN AND SETTING

A longitudinal study of 13,548 participants from a cohort study of French workers. Follow-up data covered the 1989-2000 period. Adjusted hazards ratios (HR(adj)) for serious accidents were computed by Cox's proportional hazards regression with time-dependent covariates adjusted for age, occupation, annual mileage in 2001, alcohol consumption, and number of reported health problems.

RESULTS

Men who reported treated dental or gingival problems (HR(adj)=8.57, 95% confidence interval CI=2.70-27.2) and women who reported treated renal colic or kidney stones (HR(adj)=9.71, 95% CI=2.40-39.3) were much more likely to have a serious traffic accident. Treated glaucoma, hiatal hernia or gastric ulcers, and diabetes among women and treated cataract among men were also found to be associated with the risk of serious traffic accidents.

CONCLUSIONS

This study raises the hypothesis that pain and pain treatment (singly or in combination) could increase the risk of road traffic accident and confirms that medical conditions traditionally found to be associated with traffic accident involvement of older drivers are also risk factors for middle-aged drivers.

Driving ability in schizophrenic patients: effects of neuroleptics

Recent studies indicate that individuals with schizophrenia have a two-fold incidence of traffic accidents. Cognitive and psychomotor impairment as a core feature of schizophrenia and the effects of neuroleptic treatment play an essential role in this respect. Few experimental studies have been conducted so far looking at the effects of neuroleptics on driving ability in schizophrenia. Controlled, randomised trials are totally missing. The limited database indicates that most schizophrenic patients show significant impairment in cognitive functions relevant for driving ability compared to healthy controls. There is some but limited evidence that patients under novel atypical neuroleptics show less impairment compared to conventional neuroleptics. More clinical and experimental studies are warranted.

The impact of antipsychotics on psychomotor performance with regards to car driving skills

Cognitive and psychomotor impairments are a core feature of most patients with schizophrenia and may have an important influence on driving ability. The present study investigated the effects of neuroleptic monotherapy on psychomotor functions related to car driving skills in schizophrenic patients. Consecutively admitted schizophrenic inpatients (n = 120) were tested under steady state plasma level conditions before discharge to outpatient treatment. Patients met the International Classification of Diseases, Tenth Revision criteria for schizophrenia. The study followed a naturalistic nonrandomized design. Data were collected with the computerized Act & React Testsystem and were analyzed according to medication, severity of illness, and age. Only 32.5% of the schizophrenic inpatients passed the tests without major impairments. Patients treated with atypical neuroleptics or clozapine showed a better test performance on skills related to driving ability when compared with patients on typical neuroleptics. Differences were most pronounced in measures of divided attention, stress tolerance, and attention. Data also suggest that treatment with clozapine had an overall positive impact on measures of reactivity and stress tolerance. These results show that even under steady state pharmacologic conditions psychomotor functions of most schizophrenic patients partly remitted must be considered as impaired. To evaluate these effects, a systematic neuropsychologic examination is recommended.

Fahrtüchtigkeit und psychische Erkrankung

Zusammenfassung: Psychische Erkrankungen gehen oft mit Störungen der Informationsverarbeitung einher, die bei den Betroffenen zu Beeinträchtigungen in weiten Bereichen des alltäglichen Lebens führen können. Ein Beispiel für die vielfältigen Alltagsrisiken stellt der Straßenverkehr dar. Die epidemiologische Datenlage in Bezug auf Unfallrisiken von psychiatrischen Patienten unter Psychopharmaka ist jedoch dünn und von einer Reihe von methodischen Problemen gekennzeichnet. Einige Untersuchungen weisen auf ein erhöhtes Risiko von psychiatrischen Patienten hin, in einen Verkehrsunfall verwickelt zu werden. Eine pauschale Bewertung von Arzneimitteln, die die Fahrtüchtigkeit beeinträchtigen können ist nicht möglich. Unter den potenziell verkehrsbeeinträchtigenden Psychopharmaka stehen Tranquilizer und Hypnotika an erster Stelle. Im Gegensatz zu vielen trizyklischen Antidepressiva führen neuere selektive Antidepressiva zu keinen signifikanten Beeinträchtigungen psychomotorischer und kognitiver Funktionen. Neuere atypische Antipsychotika scheinen hinsichtlich Vigilanz und Psychomotorik Vorteile gegenüber konventionellen Neuroleptika zu haben. Die Beratung und Aufklärung von Patienten zu Fragen der Fahrtauglichkeit muss individuell, unter Berücksichtigung des Krankheitsbildes, pharmaka-differenzieller Aspekte sowie beruflichen und sozialen Wiedereingliederungsbemühungen erfolgen.

Who can drive home from the emergency department? A questionnaire based study of emergency physicians' knowledge of DVLA guidelines

OBJECTIVE

To determine whether doctors working in emergency departments are aware which of the common conditions seen have driving restrictions associated with them and whether they routinely advise patients of these restrictions.

METHODS

200 questionnaires were distributed to all grades of doctor currently working in 15 emergency departments in Wessex and the south west. The survey was anonymous so follow up of non-responders was not possible. Doctors were asked to indicate which of the 20 commonly seen conditions listed had DVLA guidelines restricting driving activity at least temporarily, and in which of these conditions they actually advised patients appropriately about their driving. In addition the MDU, GMC, and the Department of Transport web site were contacted to establish what they considered to be good medical practice regarding issuing advice about driving.

RESULTS

102 doctors (51%) responded to the survey. Knowledge regarding restrictions for various conditions varied, with 87.5% responding correctly about a first fit to only 7.8% regarding a collapse query cause. With regard to advising patients, 79.4% of doctors responding said that they routinely advised patients about stopping driving after a first fit, 32% advised patients after a single transient ischaemic attack, and only 7% after a collapse query cause.

CONCLUSIONS

Doctors working in emergency departments are aware of conditions that lead to an inpatient admission that have driving restrictions. However, knowledge of conditions where patients are likely to be discharged was not as complete and advice was less likely to be given to patients. Emergency department doctors need to be more aware of restrictions that apply to conditions where patients are to be discharged.

Diabetes and driving mishaps: frequency and correlations from a multinational survey

OBJECTIVE

The intensive treatment of diabetes to achieve strict glycemic control is a common clinical goal, but it is associated with an increased incidence of hypoglycemia. Becoming hypoglycemic while driving is a hazardous condition and may lead to a greater incidence of driving mishaps. This study investigated whether diabetes is associated with increased risk of driving mishaps and correlates of such a relationship.

RESEARCH DESIGN AND METHODS

During routine visits to diabetes specialty clinics in seven U.S. and four European cities, consecutive adults with type 1 diabetes, type 2 diabetes, and nondiabetic spouse control subjects (n = 341, 332, and 363, respectively) completed an anonymous questionnaire concerning diabetes and driving.

RESULTS

Type 1 diabetic drivers reported significantly more crashes, moving violations, episodes of hypoglycemic stupor, required assistance, and mild hypoglycemia while driving as compared with type 2 diabetic drivers or spouse control subjects (P < 0.01-0.001). Type 2 diabetic drivers had driving mishap rates similar to nondiabetic spouses, and the use of insulin or oral agents for treatment had no effect on the occurrence of driving mishaps. Crashes among type 1 diabetic drivers were associated with more frequent episodes of hypoglycemic stupor while driving, less frequent blood glucose monitoring before driving, and the use of insulin injection therapy as compared with pump therapy. One-half of the type 1 diabetic drivers and three-quarters of the type 2 diabetic drivers had never discussed hypoglycemia and driving with their physicians.

CONCLUSIONS

Type 1 diabetic drivers are at increased risk for driving mishaps, but type 2 diabetic drivers, even on insulin, appear not to be at a higher risk than nondiabetic individuals. Clinical and treatment factors appear to increase risk, e.g., more frequent hypoglycemia while driving, method of insulin delivery, and infrequent self-testing before driving. Physicians are encouraged to talk to their type 1 diabetic patients about hypoglycemia and driving.

Stigma, epilepsy, and quality of life

Despite advances in the understanding and treatment of epilepsy within the past several decades, people with this disorder continue to be stigmatized by it. Though attitudes toward people with epilepsy have improved over the years, for many people with epilepsy, stigma continues to adversely impact their psychological well-being and quality of life. The stigma of epilepsy can be linked to a number of factors, including underresourced medical services, poor seizure control, and inadequate knowledge of epilepsy. Neither informal stigma nor formal discrimination is inevitable for epilepsy patients; however, for many individuals, epilepsy remains a defining feature of their identity, and such issues are a source of considerable concern for a number of patients.

Epilepsy and motor vehicle driving--a symposium held in Québec City, November 1998

BACKGROUND

This report summarizes an invitational symposium on epilepsy and Canadian laws governing motor vehicle driving held in Québec City in November 1998.

METHODS

Invited neurological experts from Canada, the USA, and Europe; and representatives of provincial and territorial licensing bodies, the Canadian Council of Motor Transport Administrators, the Canadian Medical Protective Association, and the Canadian Medical Association participated. An edited version of transcribed audiotapes was prepared. Specific issues discussed were whether or not a physician should be required to report a patient with epilepsy to the licensing authority (mandatory reporting), the nature and quantification of the risks posed by epileptic drivers, and what would be a reasonable law regulating driving by people with epilepsy in Canada.

RESULTS

The consensus among medical experts was that mandatory reporting should be abolished in Canada and that a 6-12 month seizure-free period was appropriate before most patients could return to driving private cars. Experts also believed that these standards should be uniform across Canada. There was strong disagreement with the recommendation of the Canadian Medical Association that all such drivers be reported to provincial licensing authorities even in provinces without mandatory reporting rules.

CONCLUSIONS

Physicians should be familiar with and follow the rules regarding epilepsy and driving in the provinces where they practice. Nevertheless, current evidence is against mandatory physician reporting of drivers with epilepsy and the neurologists recommended that this be abolished throughout Canada. Shorter seizure-free intervals should also be considered before resuming driving of private cars.

Traffic hypoglycaemias and accidents in patients with diabetes mellitus treated with different antidiabetic regimens

OBJECTIVES

Insulin-treated patients with diabetes are at a higher risk than the general population in causing traffic accidents due to hypoglycaemias. Preceding investigations focused on insulin-treated patients and hypoglycaemia-induced accidents as "end-points". We studied the incidence of symptomatic hypoglycaemia and hypoglycaemia-induced accidents during driving and put it in relation to the different treatment modes of insulin therapy (Conventional Insulin Treatment = CT, Intensified Conventional Insulin Treatment = ICT, Continuous Subcutaneous Insulin Infusion = CSII) as well as to patients treated with oral hypoglycaemia-inducing agents and the two main types of diabetes mellitus.

SUBJECTS AND SETTING

We investigated 450 patients (122 treated with sulphonylureas, 151 with CT, 143 with ICT and 34 with CSII) by an anonymous questionnaire at different locations to avoid bias. A total of 176 persons had type 1 diabetes, 243 persons had type 2 diabetes, 31 subjects could not be classified.

RESULTS

Symptomatic hypoglycaemias during driving were rare events with an occurrence of 0.19-8.26 (minimal and maximal mean, depending on the mode of treatment), if given as hypoglycaemias per 100 000 km on one treatment regimen, or 0.02-0.63, if given as events per year driven. Their incidence increased significantly with the degree of "strictness" between the treatment groups, except between the patients treated with ICT and CSII. Hypoglycaemia-induced accidents are rare with 0.01-0.49, if given as events per 100 000 km and 0.007-0.01, if given as events per year driven. These differences were not significant. Significant confounders influencing the traffic safety of the patients were age, duration of diabetes and concomitant antihypertensive medication. Analysing the data in accordance with the type of diabetes revealed a significantly higher rate of hypoglycaemic events in patients with type 1 diabetes. The number of hypoglycaemia-induced accidents was considerably higher in this group, but failed slightly to reach statistical significance.

CONCLUSIONS

Hypoglycaemias during driving are rare events, their occurrence is significantly influenced by the treatment regimen and type of diabetes. Hypoglycaemia-induced accidents are extremely rare, presumably as a positive effect of patient education in our group.

Psychiatric illness and subsequent traumatic brain injury: a case control study

OBJECTIVE

To determine whether psychiatric illness is a risk factor for subsequent traumatic brain injury (TBI).

METHODS

Case control study in a large staff model health maintenance organisation in western Washington State. Patients with TBI, determined by International classification of diseases, 9th revision, clinical modification (ICD-9-CM) diagnoses, were 1440 health plan members who had TBI diagnosed in 1993 and who had been enrolled in the previous year, during which no TBI was ascertained. Three health plan members were randomly selected as control subjects, matched by age, sex, and reference date. Psychiatric illness in the year before the TBI reference date was determined by using computerised records of ICD-9-CM diagnoses, psychiatric medication prescriptions, and utilisation of a psychiatric service.

RESULTS

For those with a psychiatric diagnosis in the year before the reference date, the adjusted relative risk for TBI was 1.7 (95% confidence interval (CI) 1.4 to 2.0) compared with those without a psychiatric diagnosis. Patients who had filled a psychiatric medication prescription had an adjusted relative risk for TBI of 1.6 (95% CI 1.2 to 2.1) compared with those who had not filled a psychiatric medication prescription. Patients who had utilised psychiatric services had an adjusted relative risk for TBI of 1.3 (95% CI 1.0 to 1.6) compared with those who had not utilised psychiatric services. The adjusted relative risk for TBI for patients with psychiatric illness determined by any of the three psychiatric indicators was 1.6 (95% CI 1.4 to 1.9) compared with those without any psychiatric indicator.

CONCLUSION

Psychiatric illness appears to be associated with an increased risk for TBI.

Accidents in patients with insulin-treated diabetes: increased risk of low-impact falls but not motor vehicle crashes--a prospective register-based study

BACKGROUND

Patients with diabetes mellitus may be at increased risk of accidents, mainly because of hypoglycemia. A variety of approaches have been adopted in an attempt to quantify this risk, but there has not been, to date, a systematic study using a national trauma register. In this study, we report findings from the Scottish Trauma Audit Group database.

METHODS

The database includes all patients admitted to hospital for 3 or more days, or who died in hospital as a result of their accident. The study includes 11,244 cases aged 15 years or over entered into the database between July 1996 and June 1998. This included 151 patients with insulin-treated diabetes. Using detailed prescribing information from one representative region, we have calculated the rates of different types of accidents for patients treated with insulin and compared this with the control population. We have analyzed information on the mechanism and severity of injury, outcome, and length of hospital stay.

RESULTS

Overall, the rate of accidents for insulin-treated patients was estimated at 291.2 per 100,000 population per year compared with 148.4 for the control population (p < 0.001; relative risk, 1.97; 95% confidence interval, 1.68-2.32). Insulin-treated patients were, on average, older (p < 0.005), more likely to be women (p < 0.02), and had longer stay in hospital (p < 0.001). The major excess of injuries related to low falls (< 2 m), which accounted for 62.3% of the injuries in the insulin-treated group compared with 47.1% in the remainder (p < 0.01). Low falls in the insulin-treated group (n = 94) were examined in detail: compared with the control population, there was no difference in age and sex, Injury Severity Score, Revised Trauma Score (a measure of the severity of physiologic disturbance), or calculated probability of survival (TRISS). Length of inpatient stay was higher in the insulin-treated low-fall patients (10 vs. 7 days, p < 0.01). Of the 151 catalogued injuries, the vast majority were fractures at peripheral sites. Only 23 insulin-treated individuals were admitted after a motor vehicle crash during the study period. This represents a slight but not significant increase above the rate for the background population.

CONCLUSION

This study confirms that patients taking insulin are at increased risk of accidents. Among the different types of injury, only low-impact falls were significantly increased. This is most likely related to an increased tendency for insulin-treated patients to fall during a hypoglycemic episode. However, patients with diabetes may also be at higher risk of sustaining a fracture after a fall. The number of car crashes involving drivers with insulin-dependent diabetes is small, and the rate is not significantly greater than that of the background population. Further study of the causes and consequences of falls in diabetic patients is warranted.

Driving accident frequency increased in patients with multiple sclerosis

OBJECTIVES

To assess the influence of multiple sclerosis (MS) on the ability to drive safely.

MATERIAL AND METHODS

A 10-year historical cohort register-study on 197 patients with MS and 545 controls individually matched on age, gender, place of residence, and exposure period. Persons with other neurological diseases, diabetes or abuse were excluded. The outcome measure was treatment at the emergency department after accident as a car driver.

RESULTS

Five patients and four controls had been treated, the rate per 1000 person-years with exposure being 3.4 times higher (CI 0.73-17.15) in the patients than in the control cohort. The difference is significant in one-sided test (P=0.04).

CONCLUSION

Drivers with MS were treated more often than healthy controls at a casualty department after having a road traffic accident. However, drastic consequences regarding the patients automobile driving should be avoided until these results have been substantiated by further investigations.

Evaluating the crash and citation rates of Utah drivers licensed with medical conditions, 1992-1996

BACKGROUND

Medical problems may affect the ability to drive motor vehicles, and programs that control the issuing of driver licenses to individuals with medical conditions exist in most states. The main activity of these programs is the imposition of restrictions upon the driving privileges of individuals with medical conditions that are deemed to pose some risk to public safety. However, little is known about the effectiveness of these licensing programs.

OBJECTIVE

The objective of this study was to compare the rates of adverse driving events (crash, at-fault crash and citations) experienced by drivers licensed with medical conditions to those of age-, sex- and location-matched controls. Separate comparisons were made for drivers reporting medical conditions licensed with full driving privileges, and those with restricted driving privileges (e.g. speed, area and time of day).

DESIGN

Retrospective case-control.

METHODS

The study population was all drivers licensed in the state of Utah who reported a medical condition on their driver license application, over the 5-year period 1992-1996. Drivers enter the program by self-reporting their medical problems. Control drivers were chosen from the entire population of drivers licensed in Utah for the same period. Information on driver license status, participation in the medical conditions program, citations, involvement in crashes, and death certificate data was obtained from the relevant state agencies. Probabilistic linkage methodology was used to link the records in these disparate databases for eventual analysis. Rates of citation, crashes and at-fault crashes, expressed as events per 10000 license days, were calculated separately for program drivers and their corresponding control groups for each medical condition category and restriction status. These data were used to determine an estimate of relative risk (RR) and 95% confidence intervals.

RESULTS

As a group, medical conditions drivers had modestly elevated rates of adverse driving events compared with control drivers (RR 1.09-1.74). Rates in the largest medical category, 'cardiovascular conditions', were not higher than controls. Rates were higher than control for some conditions, such as 'alcohol' and 'learning and memory', for some adverse events (RR 2.2 -5.75). Drivers with more than one medical condition appeared comparable to the general group of medical conditions program drivers.

CONCLUSIONS

Drivers in Utah medical conditions program had modestly elevated rates of adverse driving events compared to matched controls. Possible underreporting of medical conditions and accurate assessment of exposure rates are potential weaknesses in the program.

Increased driving accident frequency in Danish patients with epilepsy

OBJECTIVE

To determine driving accident frequency in a cohort of patients with epilepsy.

METHODS

A 10-year historical cohort register study of 159 subjects with epilepsy and 559 controls individually matched for age, gender, place of residence, and exposure period was carried out. All had nonprofessional driver's licenses without restrictions. Persons with recorded diagnoses of other neurologic diseases, diabetes, psychoses, seizures, abuse, or poisoning of any kind were not included. The outcome measure was treatment at the casualty department after an accident as a car driver.

RESULTS

Ten patients with epilepsy and five controls had been treated at the casualty department, the rate per 1,000 person-years with exposure being seven times higher (CI 2.18 to 26.13) in those with epilepsy than in the control cohort.

CONCLUSIONS

Drivers with epilepsy are more likely than healthy controls to be treated at a casualty department after having a motor vehicle accident.

Resumption of driving after life-threatening ventricular tachyarrhythmia

BACKGROUND

Although the privilege of driving must be respected, it may be necessary to restrict driving when it poses a threat to others. The risks associated with allowing patients with life-threatening ventricular tachyarrhythmias to drive have not been quantified.

METHODS

The Antiarrhythmics versus Implantable Defibrillators (AVID) trial compared antiarrhythmic-drug therapy with the implantation of defibrillators in patients resuscitated from near-fatal ventricular arrhythmias. In the current study, we sent patients who participated in the AVID trial a questionnaire, to be completed anonymously, requesting information about driving habits and experiences.

RESULTS

The questionnaire was returned by 758 of 909 patients (83 percent). Of these, 627 patients drove during the year before their index episode of ventricular tachyarrhythmia. A total of 57 percent of these patients resumed driving within 3 months after randomization in the AVID trial, 78 percent within 6 months, and 88 percent within 12 months. While driving, 2 percent had a syncopal episode, 11 percent had dizziness or palpitations that necessitated stopping the vehicle, 22 percent had dizziness or palpitations that did not necessitate stopping the vehicle, and 8 percent of the 295 patients with an implantable cardioverter-defibrillator received a shock. Fifty patients reported having at least 1 accident, for a total of 55 accidents during 1619 patient-years of follow-up after the resumption of driving (3.4 percent per patient-year). Only 11 percent of these accidents were preceded by symptoms of possible arrhythmia (0.4 percent per patient-year).

CONCLUSIONS

Most patients with ventricular tachyarrhythmias resume driving early. Although it is common for them to have symptoms of possible arrhythmia while driving, accidents are uncommon and occur with a frequency that is lower than the annual accident rate of 7.1 percent in the general driving population of the United States.

Should patients with psychogenic nonepileptic seizures be allowed to drive?

PURPOSE

To investigate the risk of driving accidents in patients with psychogenic nonepileptic seizures.

METHODS

First, a survey was conducted in 82 physician-members of the American Epilepsy Society to determine what they recommend in patients with psychogenic seizures in regard to driving privileges. Second, we studied a population of 20 patients with proven psychogenic nonepileptic seizures diagnosed by prolonged EEG-video monitoring. We obtained the patients' driving records from the Wisconsin Department of Transportation. We used 1991 Wisconsin crash data as the reference year. We compared the expected number of motor vehicle crashes with the observed number of crashes. chi2 with Yates' correction for continuity was used to test for statistical significance.

RESULTS

Of the 82 physicians questioned, 37 (45%) responded. Among respondents, the distribution was as follows: 49% applied the same restrictions as for patients with epilepsy; 32% did not place patients under any restrictions; and 19% decided on a case-by-case basis. The total number of reported crashes in the sample was eight, with no fatal crashes. This was not statistically significant (corrected chi2, 0.53) compared with the expected number of motor vehicle crashes for the sample.

CONCLUSIONS

This small series does not support the use of driving restrictions for patients with psychogenic nonepileptic seizures.

Vision impairment and driving

Driving is the primary mode of travel in many countries. It facilitates the performance of routine daily activities and is thus integral with the concept of quality of life. Vision is inarguably a fundamental component of safe driving. Drivers with certain eye conditions reduce their driving exposure and restrict their driving to the safest times, yet there is preliminary evidence that some eye conditions increase the risk of crashes. Visual acuity is only weakly related to crash involvement, whereas peripheral vision appears to play a more critical role. Color vision deficiency by itself is not a threat to safe driving. Based on the current literature, it is unclear whether other types of visual sensory impairment have a significant impact on driving safety and performance. Tests of visual attention and processing speed show great promise as methods of identifying high-risk drivers. There is a serious need for well-designed studies in key practical areas, such as the safety of low-vision drivers who use bioptic telescopes, the impact of monocular vision impairment on safety, and the effectiveness of vision rescreening policies after initial licensure. For ophthalmologists to guide patients about driving fitness, valid and reliable assessment tools must be developed and made widely available.

Risk factors for seizure-related motor vehicle crashes in patients with epilepsy

OBJECTIVE

We identified clinical risk factors for seizure-related motor vehicle crashes in patients with epilepsy.

BACKGROUND

Current US laws permit epilepsy patients with controlled seizures to drive. These laws attempt to balance the important economic and social value of driving with the risk to public safety from seizure-related crashes. Various clinical factors are considered in these laws, particularly the seizure-free interval. Driving restrictions range from 3 to 18 months, however, and studies have not established how these various seizure-free intervals and other clinical factors influence the risk for seizure-related motor vehicle crashes.

METHODS

We performed a retrospective case-control study to determine the influence of clinical risk factors associated with seizure-related motor vehicle crashes. Both "case" and "control" patients had epilepsy, drove, and were from the same clinic, but the cases differed in having had seizure-related crashes.

RESULTS

Fifty patients with epilepsy who crashed during seizures and 50 matched control patients were compared. Factors that significantly decreased the odds of patients with epilepsy having motor vehicle crashes due to seizures were: long seizure-free intervals, reliable auras, few prior nonseizure-related accidents, and having had their antiepileptic drugs (AEDs) reduced or switched. For example, patients who had seizure-free intervals > or = 12 months had a 93% reduced odds for crashing compared to patients with shorter intervals. Other findings were: 25% of patients had more than one seizure-related crash and 20% had missed an AED dose just prior to their crash. The majority (54%) of patients who crashed were driving illegally, with seizure-free intervals shorter than legally permitted.

CONCLUSION

Seizure-free intervals, the presence of reliable auras, AED therapy modifications, and a history of nonseizure-induced crashes should be considered when counseling patients with epilepsy on driving and when formulating driving regulatory policy. Case control studies of crashes due to seizures can help in assessing and monitoring such risks.

Diabetes and driving: towards equitable, evidence-based decision-making

In January 1998, the British government introduced new restrictions on licensing of people with insulin-treated diabetes mellitus to drive. These restrictions were based on the second EU driver licensing directive (91/4389) and looked to be costing insulin-treated diabetic individuals their entitlement to drive light goods and small passenger-carrying vehicles. In response to concerns expressed by the diabetes community in Britain, the British Diabetic Association commissioned a report examining and interpreting the available evidence of accident risk in insulin-treated diabetic patients, particularly that related to unexpected hypoglycaemia. The following article is drawn from that report.

Age-specific patterns of factors related to fatal motor vehicle traffic crashes: focus on young and elderly drivers

This population-based study examines patterns of fatal motor vehicle traffic crashes (MVTCs) by age group (16-24, 25-64, 65+) among Canadian drivers. The Canadian Traffic Accident Information Databank (TRAID) provided information about fata MVTCs between 1984 and 1993. Distribution of risk factors was compared by age group. Crude odds ratios and 95% CIs were calculated for both young and elderly drivers compared with middle-aged drivers. The middle-age group was selected as reference population since it demonstrates the lowest risk of fatality. Compared to the middle-aged group, young drivers demonstrated excess risk for (1) risk-taking behaviours and conditions, specifically alcohol and illicit drug use, speeding, non use of seat belts, fatigue and falling asleep, and inexperience; (2) crashes during the summer, during weekends and at night; and (3) single-vehicle collisions and on performing overtaking manoeuvres. Excess risk among elderly drivers was noted for (1) medical and physical conditions, inattention and inexperience; (2) driver actions, for example, improper turning, failure to yield right-to-way; (3) occurrence on weekdays and during the day; and (4) collisions at intersection and vehicle--vehicle sideswipes. The results show notable differences in risk factors by age group and confirm the need for preventive efforts that incorporate age-specific strategies.

Driving and epilepsy in Sri Lanka

Regulations regarding driving for patients with epilepsy vary from country to country. They are well implemented in developed countries, but this is not the case in countries such as Sri Lanka. The aims of this study were to study characteristics of a cohort of patients with epilepsy who were driving or riding a vehicle at present, and study the attitudes of a representative sample of doctors, patients with epilepsy and the general population regarding aspects of driving by patients with epilepsy. Patients with epilepsy attending the medical clinics at the Colombo North General Hospital, Ragama, who were driving, were given a questionnaire and interviewed in order to assess their seizure characteristics. Another questionnaire was administered to epileptic patients visiting the clinics, a sample from the general population (relatives visiting in-patients at the University Medical Unit selected randomly), doctors working at the General Hospital in Ragama and the Base Hospital in Negombo, and general practitioners in the Gampaha district, where these two hospitals are situated, which was designed to assess their views regarding driving by persons with epilepsy. Of the patients with epilepsy interviewed 24.8% were presently driving a vehicle, of them 51% were riding a motorcycle. The attitudes of the general public and patients to driving by epileptic patients were at opposite ends of the spectrum; 97% of the general public being opposed to driving by persons with epilepsy, while epileptics themselves being of the view that the rules should be lax. Doctors thought that there should be some regulations against driving by epileptic patients. These facts must be considered when setting implementable regulations regarding driving by epileptics in developing countries.

Development of a test battery to identify older drivers at risk for self-reported adverse driving events

OBJECTIVES

The purposes of this study were (1) to develop a battery of tests that assessed a wide range of functional abilities relevant to driving yet could be performed in a clinician's office and (2) to determine which of these tests were most closely associated with self-reported adverse driving events.

DESIGN

A cohort study.

SETTING

An urban community.

PARTICIPANTS

Participants were drawn from the Project Safety cohort, a probability sample of noninstitutionalized older persons in New Haven, Connecticut, initiated in 1989. The current study included surviving, active drivers in the cohort (N=125).

MEASURES

The test battery assessed visual, cognitive, and physical abilities potentially relevant to driving, and was administered in participants' homes by trained interviewers between October 1994 and July 1995. Outcome measures included the self-report of a crash, moving violation, or being stopped by police in any Project Safety interview since the inception of the cohort. Analyses compared performance on the elements of the test battery with participants' histories of adverse driving events.

RESULTS

Of the 125 drivers, 50 (40%) had reported an adverse event in a mean period of 5.76 (+/-.25) years before the current interview. The elements of the test battery independently associated with a history of events, adjusting for driving frequency, included near visual acuity worse than 20/40 (adjusted odds ratio 11.90), limited neck rotation (OR 6.10), and poor performance on a test of visual attention, the number cancellation task (OR 3.00). The resulting regression equation yielded a sensitivity of 80%, a specificity of 55%, and an area under the curve of .75 by receiver operating characteristic analysis.

CONCLUSION

These findings suggest it may be possible to identify individuals potentially at risk for self-reported adverse driving events using simple tests of functional ability. If validated, such an approach could be used to identify individuals who need a more detailed assessment of functional abilities to determine the severity and etiology of impairments, and their effect on driving performance, as well as possible interventions to correct or compensate for the impairments.

Epilepsy and driving: a survey of Canadian neurologists

BACKGROUND

A seizure is the most common cause of loss of driving privileges for medical reasons but there is variability in how physicians and the authorities who regulate driving approach this issue.

METHODS

A questionnaire regarding epilepsy and driving was sent to all adult neurologists in Canada (n = 494).

RESULTS

Of 289 (59%) neurologists responding, 50% usually report patients with seizures to the department of motor vehicles compared to only 4% for stroke/TIA, 26% for dementia and 8% for other neurologic disorders (p < 0.0001). In the five provinces with mandatory reporting laws, seizures were reported most of the time by 84% compared to only 19% in the five provinces with discretionary reporting (p < 0.0001). Nationwide, 44% agreed with mandatory reporting but this also differed in provinces with and without mandatory reporting legislation (63% vs. 37%, p < 0.0001). Only 49% agreed with the current recommendation of at least one year seizure free interval before resuming driving.

CONCLUSIONS

Seizures are disproportionately reported compared to other neurological conditions. Many neurologists disagree with the recommended Canadian standards for duration of driving restriction after seizures. Variability in the attitude and practice of neurologists in regard to reporting of seizures is confirmed.

The effect of epilepsy on road traffic accidents and casualties

A prospective study was carried out between October 1992 and June 1994 to investigate the effect of epilepsy as a risk factor in road traffic accidents (RTA) and casualties in the United Arab Emirates (UAE). The aim of this paper was to investigate the risk and effect of epilepsy on road traffic accidents and casualties and identify possible risk factors for traffic accidents and casualties and identify possible risk factors for traffic accidents and violations among these drivers. Most (70%) were young drivers and under age 40 years; 43% were UAE nationals; 41% had a primary school education; 48.8% had a full license to drive private or commercial taxis; 41% had less than two years driving experience and 17.1% used seat bolts regularly. Most (65.9%) admitted to crossing red traffic lights; 46.3% to parking in forbidden areas; 66% to speeding; 36% to smoking while driving; 34.1% to using the telephone whilst driving; 43.9% to putting their child in the front seat; 20.8% had been previously involved in an RTA; and 53.7% had sustained serious injury. A figure of 34.1% had at least one seizure per year and 26.8% had at least one seizure per month. The most common violations were careless driving (34.1%) and traffic regulation violations (24.4%). Significantly higher risk was observed for property damage (RR = 1.85; 95% CI = 0.64-5.14) and traffic violations (RR-1.91; 95% CI = 0.54-2.29). In the UAE there are no restrictions on the issue of driving licenses to people prone to epileptic seizures. In conclusion, it is emphasized that patients with conditions such as epilepsy should feel obliged to inform the traffic authorities or the health authorities about their condition. It seems likely that the problem could be greatly reduced if appropriate action was taken concerning epileptic drivers. It is hoped that the results and recommendations of this study will be useful to traffic and health authorities.

Risk of accidents in drivers with epilepsy

OBJECTIVE

To estimate the risks of road traffic accidents over a period of three years in drivers with a history of single seizures or epilepsy, and to compare them with a cohort of drivers followed up by the Transport Research Laboratory (TRL).

DESIGN

A retrospective survey of driving and accident experience by self-completion questionnaire.

SUBJECTS

16,958 drivers with a previous history of epilepsy responding to the survey and 8888 non-epileptic drivers responding to a TRL survey.

MAIN OUTCOME MEASURES

The risk of any accident, any accident producing an injury, and any accident producing a serious injury, over a three year period.

RESULTS

After adjustment for differences in age, sex, driving experience, and mileage between the two populations there was no evidence of any overall increase in risk of accidents in the population of drivers with a history of epilepsy. However, there was evidence of an increased risk of more severe accidents in the population with epilepsy. The risk was increased by about 40% for serious injuries and there was evidence of a twofold risk of increase in non-driver fatalities. These increases seem largely explicable by the occurrence of seizures in this population during the three years of driving that the survey covered.

CONCLUSIONS

The acceptability of driving for people with a history of epilepsy should be determined by an acceptable risk of accidents resulting in injury or serious injury rather than overall accident rates. As people with epilepsy can now drive after a 12 month seizure free period rather than the required two year period when this survey was undertaken, it is important to ascertain whether there is any increased risk of injury associated accidents with this policy.

Medical conditions, risk exposure, and truck drivers' accidents: an analysis with count data regression models

Recent studies do not agree on the possible relationship between medical conditions and traffic safety; most of them do not control for exposure factors. This problem has become more pertinent for scientific studies because of litigation that showed that present regulations about access to driver permits might contravene human rights legislation. In our study, we estimate the effect of different medical conditions on truck drivers' distributions of accidents. Our data and our models permit simultaneous control for age; medical conditions; exposure factors measured by hours, kilometer, and qualitative factors; and other characteristics of truck drivers. Our results show that diabetic truck drivers of the permit class for straight trucks have more accidents than drivers in good health. No other studied medical condition has a significant effect on individual accident distributions. Many risk exposure variables are also significant. The effect of age is discussed in detail.

Medical conditions and motor vehicle collision injuries in older adults

OBJECTIVE

To determine whether medical conditions that can impair sensory, cognitive, or motor function increase the risk of injury due to motor vehicle collision in older drivers.

DESIGN

Case-control study.

SETTING

Group Health Cooperative of Puget Sound, a large prepaid health plan.

PARTICIPANTS

Group Health members age 65 or older who were licensed drivers in 5 counties. Cases were injured while driving during 1987 or 1988. Controls were matched to cases on age, gender, and county of residence but experienced no such injury during the study years.

MEASUREMENTS

The outcome was injury requiring medical care due to a police-investigated motor vehicle collision. Risk factors evaluated included selected medical conditions active within the previous 3 years, as determined from the medical record.

MAIN RESULTS

Injury risk was 2.6-fold higher in older diabetic drivers (95% CI: 1.4-4.7), especially those treated with insulin (odds ratio [OR] = 5.8, 95% CI: 1.2-28.7) or oral hypoglycemic agents (OR = 3.1, 95% CI: 0.9-11.0), those with diabetes for over 5 years (OR = 3.9, 95% CI: 1.7-8.7), and those with both diabetes and coronary heart disease (OR = 8.0, 95% CI: 1.7-37.7). Increases were also found for older drivers with coronary artery disease (OR = 1.4), depression (OR = 1.7), alcohol abuse (OR = 2.1), or falls (OR = 1.4), but these associations could easily have arisen by chance.

CONCLUSIONS

Counseling about driving risks may be warranted for certain elderly diabetic drivers. Further research is needed to determine whether transient hypoglycemia or long-term complications explain these effects.

Epilepsy and driving: an international perspective. Joint Commission on Drivers' Licensing of the International Bureau for Epilepsy and the International League Against Epilepsy

Individuals with a history of seizures may be granted driving privileges if the risks of future seizure while driving are relatively low. Different nations have defined these risks in a wide variety of ways. Some countries, e.g., Japan, Greece, Brazil, India, and Russia, preclude driving after a single seizure. Other countries, such as Canada and the United States, allow driving < or = 3 months after certain types of seizures. A Joint Commission of the International Bureau for Epilepsy/International League Against Epilepsy has summarized regulations in several countries. From a consideration of medical literature and existing practices, a series of proposed guidelines for driving and epilepsy is recommended. In general, these guidelines suggest use of a seizure-free interval, generally 1-2 years but less in particular instances, to determine fitness to drive. Required physician reporting is discouraged, but physicians should report patients whom they believe pose a danger to themselves and to public safety. Individualized consideration should be given to special circumstances that may modify a general driving prohibition. Education and information programs are necessary for medical and regulatory authorities to develop a rational approach to driving and epilepsy worldwide.

Epilepsy and Driving: Attitudes and Practices among Patients Attending a Seizure Clinic

Although the loss of freedom to drive is a serious consequence of the diagnosis of epilepsy, it is unclear how well current regulations are understood and adhered to by patients. Using questionnaires completed anonymously, we assessed attitudes and practices among 104 patients with epilepsy. Seventeen (16%) patients were driving, three illegally. In total, eight (8%) patients had at some stage driven illegally, even though seven admitted to having been warned not to do so. Even among the 14 patients currently driving and eligible to do so, only eight (57%) had informed the licensing authority and six (43%) their insurers. Only 34 (33%) patients showed satisfactory knowledge of current regulations, including seven (50%) of those currently driving and 21 (50%) of 42 patients who expressed a wish to drive in the future. Of these 34, only 14 (41%) expressed complete agreement with the regulations.

Thus, a significant proportion of patients with epilepsy has driven illegally or has failed to inform the licensing authority or insurers. Understanding of regulations is poor. Less stringent restrictions have been shown to be safe in other countries and might improve compliance.

Global regulations on diabetic treated with insulin and their operation of commercial motor vehicles. DiaMond Project Group on Social Issues

Governments often regulate who may and may not drive vocationally for public safety purposes. Recent arguments, however, imply that employment opportunities may be limited unnecessarily for people with medical impairments. Drivers with diabetes treated with insulin are commonly perceived to pose an increased risk of accidents because of their susceptibility to hypoglycaemia. Much uncertainty, though, surrounds the data on the risks of these drivers. An international survey studied the licensing policies applied to professional lorry drivers with diabetes treated with insulin. Responses from 24 countries indicated that regulations differ considerably; ranging from a complete ban on professional driving to no restrictions at all. Many reasons may explain this difference, including the lack of data on the effects of hypoglycaemia on the incidence of traffic accidents. A proper account of the risks of diabetic drivers is necessary to balance fairly the rights of employment against the risks.

Attitudes of physicians toward elderly drivers and driving policy

OBJECTIVE

To examine physicians' attitudes toward and knowledge concerning driving in older persons.

DESIGN

Questionnaire survey.

MEASUREMENTS

A questionnaire was sent to physician members of the American Geriatrics Society (n = 5009). The questionnaire explored physicians' practice characteristics, general approach to record keeping, frequency of behavior toward educating, counseling, and reporting patients to authorities when deemed appropriate, and their personal understanding of driving issues and physician responsibilities within the state in which they practice.

RESULTS

A response rate of 48% was obtained. There was a lack of consensus among physicians, with a broad range of attitudes and practices dealing with this growing public health concern. Physicians generally believed that they had a legal responsibility to assess driving ability but were uncertain about how to assess driving competence and their responsibility toward their senior patients who drive.

CONCLUSIONS

Physician practices concerning the appropriate management of older drivers vary widely. Physicians should be aware that medical literature is available to aid in the evaluation of the elderly driver with medical impairments. In addition, physicians should consider referring their elderly patients to driver refresher courses to improve or maintain their driving skills. More research is needed to help guide health professionals in assessing the frail elder with multiple medical impairments and decreasing the crash risk for the older driver.

Epilepsy: patient perceptions of their condition

The objective of this study was to ascertain the perceptions of people with epilepsy about their condition. Nine hundred and eight questionnaires were sent to members of epilepsy associations, with a 45% response rate, and 625 questionnaires were sent to neurologists for their patients to complete, with a response rate of 16.5%. The results reinforce and extend previous observations that there is an ongoing need for educating health care professionals and persons with epilepsy about the condition. Matters pertaining to driving, the unpredictability of seizures, lack of employment and cognitive difficulties were of major concern to the respondents. The present data also highlighted the vexed relationship between stress and seizure control, which needs to be further investigated. These data should be of value to doctors and other health care professionals in their dealings with people with epilepsy. It should also provide epilepsy associations with data upon which they might be able to plan education services.

The law and medical fitness to drive--a study of doctors' knowledge

We assessed doctors' knowledge on laws and recommendations regarding fitness to drive in certain medical conditions by a questionnaire survey. A total of 646 doctors consisting of 400 general practitioners and 246 hospital doctors of all grades were circulated with the questionnaire. The survey was anonymous so non-responders could not be re-circulated. The response rate was 26% general practitioners and 32% (hospital doctors). The results show the poor knowledge of doctors on several aspects of fitness to drive. It is necessary for all doctors to have a basic knowledge on the laws and recommendations on fitness to drive so that they can advise their patients correctly. Our survey clearly shows that doctors' knowledge is poor. Many drivers may therefore be placing themselves and others at risk. It is mandatory that this subject receives more attention in undergraduate and postgraduate education and that doctors should be regularly updated on new recommendations from the Driver and Vehicle Licensing Agency.

Epilepsy, driving laws, and patient disclosure to physicians

To avoid loss of driving privileges, patients with epilepsy may elect not to report seizures to their physician or to the Department of Motor Vehicles (DMV). Reporting to the physician may differ depending upon the type of law in effect, i.e., mandatory physician reporting versus patient reporting to the DMV. Nondisclosure to the physician may have important consequences with regard to seizure management. We surveyed patients at two adult seizure clinics to determine the effect of driving laws on patients' reporting to their physician. One hundred fifty-eight patients completed an anonymous questionnaire asking whether they would report a breakthrough seizure under a physician versus a patient DMV reporting system. Under patient reporting, 96% would inform their physician and 56% would report to the DMV. Under physician reporting, 84% would inform their physician. This falls to 72% when considering currently driving patients only. An additional 9-17% of patients would continue to drive with a suspended license. In all, 53% would remain driving under patient reporting and 33% under physician reporting; however, with physician reporting, half of the illegally driving patients would have compromised their medical care, potentially increasing driving risk.

Total patient care in epilepsy

The aim of total care in epilepsy is to ensure the best possible management for each individual patient. Although pharmacotherapy for reduction or suppression of seizures is the basis of treatment in epilepsy, social and environmental problems are as likely to distress patients as continuing seizures. One often neglected aspect of management is the provision of adequate information for patients and relatives with regard to the various aspects of the seizure disorder. Better education of society regarding epilepsy is necessary to remove the many preconceptions and prejudices that still prevail. It is important to encourage self-confidence in the patient and to avoid overprotection. Restrictions on lifestyle, including driving and employment, should be decided on a case-by-case basis, and only imposed if really necessary. Patients with epilepsy refractory to treatment should have access to specialized referral centers and institutions. One of the major goals of total patient care should be to help the patient with a seizure disorder lead a normal life, insofar as this is not prevented by additional mental retardation or cognitive dysfunctions.

Epilepsy and driving: a survey of automobile accidents attributed to seizure

From results of a survey of 72 epileptic car drivers who had a mean driving history of 8.6 years, 18 (25%) had experienced one or more automobile accidents ascribed to a seizure while driving, with the total number of accidents of the surveyed group amounting to 35. All the drivers were known to have partial epilepsy, 13 of them having temporal lobe epilepsy. The main characteristics of these 35 accidents were as follows: (1) Fifty-seven percent were caused by complex partial seizure without an aura in which consciousness was immediately impaired at onset, while about 10% were attributed to simple partial seizure in which the conscious state was not altered. No accident was caused by a first seizure; (2) Fifty-one percent occurred on an empty road with little pedestrian and/or vehicular traffic; (3) In about half the accidents, the driver's vehicle collided against an immovable object, and only 20% involved crashing into another car; (4) Most accidents caused damage to only the driver's car and/or mild physical injury; and (5) Fifty-four percent of the accidents were not reported to the police, and many that were reported were ascribed to driving while asleep, to careless driving or to similar behavior.

A study on driving status in 98 epileptic patients with driving licences

As to the driving status in the period between January 1984 and December 1988, 98 epileptic patients with driving licences were examined, paying regard to their clinical conditions. Sixty-one (62%) of the patients were seizure-free for the last five years or more in December 1988. Eighty-one (83%) were actually driving motor vehicles at the time of this study, and 27 (33%) of the 81 drivers still had fits during the past five years. Nine patients (9%) had caused traffic accidents, but no accident had occurred due to seizures. The type of the nine accidents was as follows: One case of a slight physical injury to the other person, four cases of the driver's own car damage without other material damage, and four of the accidents involving other cars.

Assessing driving capability: a method for individual testing: the significance of paraparesis inferior studied in a controlled experiment

The part played in traffic safety by driver illness or disability is uncertain or unknown. So also are the specific identity and degree of the disorders which necessitate the use of driving aids or which completely incapacitate a person from driving. Despite the gravity of the problems, the question of fitness to hold a driving licence is decided throughout the world mainly on the basis of subjective assessment. Controlled experiments exploring the significance of disorders have only been carried out on a restricted scale. In this paper a description is given of a mock car, which is used both for research and individual assessment. It enables the measurement of strength application, steering wheel turn speed, simple reaction times when operating pedals and steering wheel, erroneous reactions, and choice reaction times. Experiments involving 109 able-bodied and healthy persons showed, as expected, that the muscular strength of men was greater than of women, and that men were significantly quicker at carrying out functions which primarily depend upon speed of movement and of strength. Apart from this, however, there were no significant sex-related differences. Almost all variables showed age dependence, this being most pronounced in the case of men. Thirty-two percent of the test candidates committed errors like braking instead of turning the wheel or turning to the wrong side. Neither the incidence nor the seriousness of errors bore any relation to sex or age. Fifty-two persons suffering from paraparesis inferior were compared with the 109 able-bodied subjects. The degree of paresis co-varied with reaction times, but the degree of spasticity only to a minor extent. The results indicate that at a speed of 80 km/h, 'slight paresis' increases reaction distance by around 2-3 m (15%), and 'moderate paresis' by the region of 50 m.

The effect of epilepsy or diabetes mellitus on the risk of automobile accidents

BACKGROUND

Previous studies of possible associations between chronic medical conditions and traffic safety have been inconsistent and subject to bias because of the incomplete identification of affected persons. Recent advances in the diagnosis and management of epilepsy and diabetes mellitus have improved the control of these disorders and suggest a need to reexamine the risk of traffic mishaps among patients with these conditions.

METHODS

We conducted a population-based retrospective cohort study of 30,420 subjects 16 to 90 years of age, with and without epilepsy or diabetes mellitus. Subjects included all the licensed drivers in seven contiguous ZIP Code areas in which the Marshfield Clinic and St. Joseph's Hospital, Marshfield, Wisconsin, are the primary sources of medical care. Standardized rates of moving violations and accidents over a four-year period (1985 through 1988) were compared in affected and unaffected cohorts.

RESULTS

Standardized mishap ratios for subjects with diabetes were 1.14 for all moving violations (P = 0.23) and 1.32 for accidents (P = 0.01); for subjects with epilepsy the ratios were 1.13 for moving violations (P = 0.26) and 1.33 for accidents (P = 0.04).

CONCLUSIONS

We conclude that drivers with epilepsy or diabetes mellitus have slightly increased risks of traffic accidents as compared with unaffected persons. The increases in risk observed in our study were generally smaller than those in previous studies, and we believe they are not great enough to warrant further restrictions on driving privileges.