ADA 2013: 糖尿病和驾驶

Diabetes and Driving AMERICAN DIABETES ASSOCIATION O f the nearly 19 million people in theU.S. with diagnosed diabetes (1), alarge percentage will seek or cur- rently hold a license to drive. For many, a driver’s license is essential to work; taking care of family; securing access to public and private facilities, services, and institutions; interacting with friends; attending classes; and/or performingmany other functions of daily life. Indeed, in many communities and areas of the U.S. the use of an automo- bile is the only (or the only feasible or af- fordable)means of transportation available. There has been considerable debate whether, and the extent to which, diabetes may be a relevant factor in determining driver ability and eligibility for a license. This position statement addresses such issues in light of current scientific and medical evidence. Sometimes people with a strong in- terest in road safety, including motor vehi- cle administrators, pedestrians, drivers, other road users, and employers, associate all diabetes with unsafe driving when in fact most people with diabetes safely oper- ate motor vehicles without creating any meaningful risk of injury to themselves or others. When legitimate questions arise about the medical fitness of a person with diabetes to drive, an individual assessment of that person’s diabetes managementdwith particular emphasis on demonstrated abil- ity to detect and appropriately treat poten- tial hypoglycemiadis necessary in order to determine any appropriate restrictions. The diagnosis of diabetes is not sufficient to make any judgments about individual driver capacity. This document provides an overview of existing licensing rules for people with diabetes, addresses the factors that impact driving for this population, and identifies general guidelines for assessing driver fit- ness and determining appropriate licensing restrictions. LICENSING REQUIREMENTSdPeople with dia- betes are currently subject to a great variety of licensing requirements and restrictions. These licensing decisions occur at several points and involve different levels and types of review, depending on the type of driving. Some states and local jurisdictions impose no special requirements for people with diabetes. Other jurisdictions ask driv- ers with diabetes various questions about their condition, including their manage- ment regimen and whether they have ex- perienced any diabetes-related problems that could affect their ability to safely oper- ate a motor vehicle. In some instances, answers to these questions result in restric- tions being placed on a person’s license, in- cluding restrictions on the type of vehicle theymay operate and/or where theymay op- erate that vehicle. In addition, the rules for operating a commercial motor vehicle, and for obtaining related license endorsements (such as rules restrictingoperationof a school bus or transport of passengers or hazardous materials) are quite different and in many ways more cumbersome for people with di- abetes, especially those who use insulin. With the exception of commercial driving in interstate commerce (Interstate commercial driving is defined as trade, traffic or transportation in theUnited States between a place in a state and a place outside of such a state, between two places in a state through another state or a place outside of the United States, or between two places in a state as part of trade, traffic or transportation originating or terminat- ing outside the state or the United States [2]), which is subject to uniform federal regulation, both private and commercial driving are subject to rules determined by individual states. These rules vary widely, with each state taking its own approach to determining medical fitness to drive and the issuance of licenses. How diabetes is identified,which people aremedically eval- uated, and what restrictions are placed on people who have experienced hypoglyce- mia or other problems related to diabetes all vary from state to state. States identify drivers with diabetes in a number of ways. In at least 23 states, drivers are either asked directly if they have diabetes or are otherwise required to self-identify if they have diabetes. In other states drivers are asked some variation of a question about whether they have a con- dition that is likely to cause altered percep- tion or loss of consciousness while driving. In most states, when the answer to either question is yes, the driver is required to submit to a medical evaluation before he or she will be issued a license. Medical evaluation Drivers whose medical conditions can lead to significantly impaired consciousness are evaluated for their fitness to continue to drive. For people with diabetes, this typi- cally occurswhen a person has experienced hypoglycemia (3) behind the wheel, even if this did not result in a motor vehicle acci- dent. In some states this occurs as a result of a policy to evaluate all people with di- abetes, even if there has been no triggering event. It can also occur when a person ex- periences severe hypoglycemia while not driving and a physician reports the episode to the licensing authority. In a handful of states, such reporting by physicians isman- datory. In most other states physicians are permitted to make reports but are given discretion to determine when such reports are necessary. Some states specify that physiciansmay voluntarily report those pa- tients who pose an imminent threat to pub- lic safety because they are driving against medical advice. Physicians and others re- quired to make reports to the licensing au- thority are usually providedwith immunity from civil and criminal actions resulting from the report. When licensing authorities learn that a driver has experienced an episode of hypoglycemia that potentially affected the ability to drive, that driver is referred for a medical evaluation and in many cases will lose driving privileges for a period of time until cleared by the licensing au- thority. This period can range from 3 to 6 months or longer. Some state laws allow for waivers of the rules when the episode is a one-time event not likely to recur, for c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c Peer reviewed by the Professional Practice Committee, September 2011, and approved by the Executive Committee of the American Diabetes Association, November 2011. DOI: 10.2337/dc13-S080 © 2013 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and thework is not altered. See http://creativecommons.org/ licenses/by-nc-nd/3.0/ for details. S80 DIABETES CARE, VOLUME 36, SUPPLEMENT 1, JANUARY 2013 care.diabetesjournals.org P O S I T I O N S T A T E M E N T example because of a change in medication or episodes that occur only during sleep. Medical evaluation procedures vary and range from a simple confirmation of the person’s diabetes from a physician to a more elaborate process involving a state medical advisory board, hearings, and presentation and assessment of medical evidence. Some states convene medical advisory boards with nurses and physi- cians of different specialties who review and make recommendations concerning the licensing of people with diabetes and other medical conditions. In other states, licensing decisions are made by adminis- trative staff with little or no medical train- ing and with little or no review by a medical review board or by a physician or physicians with any relevant expertise concerning medical conditions presented by individual applicants. The medical evaluation process for commercial drivers occurs at predeter- mined intervals, typically every 2 years. Unlike noncommercial licenses, these regular evaluations are not linked to episodes of severe hypoglycemia but are part of an ongoing fitness evaluation for jobs requiring commercial driving. The fed- eral government has no diabetes-specific restrictions for individuals who manage their disease with diet, exercise, and/or oral medication. It offers an exemption program for insulin-using interstate com- mercial drivers and issues medical certifi- cates to qualified drivers. Factors in the federal commercial driving medical evalu- ation include a review of diabetes history, medications, hospitalizations, blood glu- cose history, and tests for various com- plications and an assessment of driver understanding of diabetes and willingness to monitor their condition. SCIENCE OF DIABETES AND DRIVINGdHypoglycemia indicating an impaired ability to drive, retinopathy or cataract formation impairing the vision needed to operate a motor vehicle, and neuropathy affecting the ability to feel foot pedals can each impact driving safety (4). However, the incidence of these conditions is not sufficiently extensive to justify re- striction of driving privileges for all drivers with diabetes. Driving mishaps related to diabetes are relatively infrequent for most drivers with diabetes and occur at a lower rate than mishaps of many other drivers with conditions that affect driving perfor- mance and that are tolerated by society. However, just as there are some pa- tients with conditions that increase their risk of incurring driving mishaps, such as unstable coronary heart disease, obstruc- tive sleep apnea, epilepsy, Parkinson’s disease, or alcohol and substance abuse, there are also some drivers with diabetes that have a higher risk for driving mis- haps. The challenges are to identify high- risk individuals and develop measures to assist them to lower their risk for driving mishaps. Understanding the risk of diabetes and driving In a recent Scottish study, only 62% of health care professionals suggested that insulin-treated drivers should test their blood glucose before driving; 13% of health care professionals thought it safe to drive with blood glucose,72mg/dL (4mmol/L), and 8% did not know that impaired aware- ness of hypoglycemia might be a contrain- dication to driving (5). It is important that health care professionals be knowledgeable and take the lead in discussing risk reduc- tion for their patients at risk for hypoglyce- mia. In a large international study, nearly half of drivers with type 1 diabetes and three-quarters of those with type 2 diabetes had never discussed driving guidelines with their physician (8). A meta-analysis of 15 studies sug- gested that the relative risk of having a motor vehicle accident for people with diabetes as a whole, i.e., without differen- tiating those with a significant risk from those with little or no risk, as compared with the general population ranges be- tween 1.126 and 1.19, a 12–19% in- creased risk (6). Some published studies indicated that drivers with type 1 diabetes have a slightly higher risk, with a relative risk ratio of ;2 (7,8,9), but this was not confirmed by other studies (10). Two stud- ies even suggested that there is no increased risk associated with insulin-treated diabe- tes (11,12), but the methodologies used have been criticized (13). This increased risk of collisions must be interpreted in the light of society’s tol- erance of other and much higher–risk conditions. For example, 16-year-old males have 42 times more collisions than 35- to 45-year-old women. If the heaviest car collides with the lightest car, the driver of the latter is 20 times more likely to be killed than the driver of the former. The most dangerous rural highways are 9.2 times more dangerous than the safest urban highways. Driving at 1:00 A.M. on Sunday is 142 times more dangerous than driving at 11:00 A.M. (7). Driverswith attention deficit/ hyperactivity disorder have a relative risk ratio of;4 (14), whereas those with sleep apnea have a relative risk of ;2.4 (15). If society tolerates these conditions, it would be unjustified to restrict the driving priv- ileges of an entire class of individuals who are at much lower risk, such as drivers with diabetes. The most significant subgroup of persons with diabetes for whom a greater degree of restrictions is often applied is drivers managing their diabetes with in- sulin. Yet, when the type of diabetes is controlled for, insulin therapy per se has not been found to be associated with in- creased driving risk (3,16,17). While im- paired awareness of hypoglycemia has been found to relate to increased incidence of motor vehicle crashes in some studies (12), it has not been found to be a relevant variable in other studies (4,7,23). The sin- gle most significant factor associated with driving collisions for drivers with diabetes appears to be a recent history of severe hy- poglycemia, regardless of the type of diabe- tes or the treatment used (1,3,18–21). The American Diabetes Association Workgroup on Hypoglycemia defined se- vere hypoglycemia as low blood glucose resulting in neuroglycopenia that disrupts cognitive motor function and requires the assistance of another to actively administer carbohydrate, glucagon, or other resuscita- tive actions (22). In a prospective multicen- ter study of 452 drivers with type 1 diabetes followed monthly for 12 months, 185 par- ticipants (41%) reported a total of 503 epi- sodes of moderate hypoglycemia (where the driver could still treat him/herself but could no longer drive safely) and 23 partic- ipants (5%) reported 31 episodes of severe hypoglycemia (where the driver was unable to treat him/herself) while driving (21). Conversely, the Diabetes Control andCom- plications Trial (DCCT) group reported 11 motor vehicle accidents in 714 episodes of severe hypoglycemia, a rate of 1.5% (23). The significant impact of moderate hypoglycemia while driving is supported by multiple studies demonstrating that moderate hypoglycemia significantly and consistently impairs driving safety (24–26) and judgment (27,28) as towhether to con- tinue to drive or to self-treat (29,30) under such metabolic conditions. In one study, 25% of respondents thought it was safe to drive even when blood glucose was ,70 mg/dL (3.9 mmol/L) (31). While significant hyperglycemia may impair cognitive, motor, and perceptual functioning (32–35), there is only one re- port suggesting extreme hyperglycemia can impact driving safety (36). Thus, care.diabetesjournals.org DIABETES CARE, VOLUME 36, SUPPLEMENT 1, JANUARY 2013 S81 Position Statement efforts to equate hyperglycemia with driv- ing impairment are currently not scientif- ically justified. Individual differences Eighty percent of episodes of severe hy- poglycemia affect about 20% of people with type 1 diabetes (37–39). Available data suggest that a small subgroup of driv- ers with type 1 diabetes account for the majority of hypoglycemia-related colli- sions (9,30,40). When 452 drivers with type 1 diabetes were followed prospec- tively for a year, baseline reports of prior episodes of mild symptomatic hypoglyce- mia while driving or severe hypoglycemia while driving, hypoglycemia-related driv- ing mishaps, or hypoglycemia-related collisions were associated with a higher risk of driving mishaps in the following 12 months by 3, 6, 6, and 20%, respec- tively. Risk increased exponentially with additional reported episodes: If individu- als had two episodes of severe hypoglyce- mia in the preceding 12 months their risk increased to 12%, and two collisions in the previous 2 years increased their risk by 40%. The strongest predictors in- volved a history of hypoglycemia while driving (21). Laboratory studies that com- pared drivers with type 1 diabetes who had no history of hypoglycemia-related driving mishap in the past year to those who had more than one mishap found that those with a history of mishaps: 1) drove significantly worse during progres- sive mild hypoglycemia (70–50 mg/dL, 3.9–2.8 mmol/L) but drove equally well when blood glucose was normal (euglyce- mia); 2) had a lower epinephrine response while driving during hypoglycemia, 3) were more insulin sensitive, and 4) demon- strated greater difficulties with working memory and information processing speed during euglycemia and hypoglycemia (24,40,41). Thus, a history of mishaps should be used as a basis for identifying insulin-managed drivers with elevated risk of future mishaps. Such individuals are appropriately subjected to additional screening requirements. Four studies have demonstrated that Blood Glucose Awareness Training (BGAT) reduces the occurrence of colli- sions and moving vehicle violations while improving judgment about whether to drive while hypoglycemic (42–45). BGAT is an 8-week psycho-educational training program designed to assist individuals with type 1 diabetes to better anticipate, prevent, recognize, and treat extreme blood glucose events. This intervention can be effectively delivered over the inter- net (46). Diabetes Driving (diabetesdriv- ing.com), a program funded by the National Institutes of Health, is another internet-based tool to help assess the risk of driving mishaps and assist high- risk drivers to avoid hypoglycemia while driving and to better detect and manage hypoglycemia if it occurs while driving. RECOMMENDATIONS Identifying and evaluating diabetes in drivers Individuals whose diabetes poses a sig- nificantly elevated risk to safe driving must be identified and evaluated prior to getting behind the wheel. Because people with diabetes are diverse in terms of the nature of their condition, the symptoms they experience, and the measures they take to manage their diabetes, it is impor- tant that identification and evaluation pro- cesses be appropriate, individualized, and based not solely on a diagnosis of diabetes but rather on concrete evidence of actual risk. Laws that require all people with diabetes (or all people with insulin-treated diabetes) to be medically evaluated as a condition of licensure are ill advised be- cause they combine people with diabetes into one group rather than identifying those drivers who may be at increased risk due to potential difficulties in avoiding hypoglycemia or the presence of compli- cations. In addition, the logistics of regis- tering and evaluating millions of people with diabetes who wish to drive presents an enormous administrative and fiscal bur- den to licensing agencies. States that require drivers to identify diabetes should limit the identification to reports of diabetes- related problems. To identify potentially at-risk drivers, a short questionnaire can be used to find those drivers who may require further evaluation. The questionnaire should ask whether the driver has, within the past 12 months, lost consciousness due to hypo- glycemia, experienced hypoglycemia that required intervention from another per- son to treat or that interfered with driving, or experienced hypoglycemia that devel- oped without warning. The questionnaire should also query about loss of visual acuity or peripheral vision and loss of feeling in the right foot. Inasmuch as obstructive sleep apnea is more common in people with type 2 diabetes than in the nondiabetic population, patients should be queried about falling asleep during the day. Any positive answer should trigger an evaluation to determine whether restric- tions on the license or mechanical mod- ifications to the vehicle (e.g., hand controls for people with an insensate foot) are necessary to ensure public safety. It is ill-advised to determine risk for driving mishaps based on a driver’s gly- cosylated hemoglobin because episodic transitions into hypoglycemia, not average blood glucose, increases risk of driving mishaps. Evaluation of drivers with diabetes must include an assessment by the treat- ing physician or another diabetes special- ist who can review recent diabetes history and provide to the licensing agency a recommendation about whether the driver has a condition that impairs his or her ability to safely operate a motor vehicle. The treating physician or another physician who