Diabetes and Driving
Diabetes and driving
Effects of diabetes on ability to drive
Diabetes and the risk of road traffic accidents
Current legislation in South Africa
Recommendations for the South African situation
Non-driving period after a ‘severe hypoglycaemic event'
Reduced awareness of hypoglycaemia
Comorbidities and end-organ complications
(See Strength of Recommendations Taxonomy (SORT) for explanation of Grade A-C)
| SEMDSA 2017 Recommendations | |
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Patients must be educated that diabetes can affect driving performance because of chronic complications that impair sensory or motor functions and because of transient cognitive dysfunction resulting from medication-induced hypoglycaemia
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C |
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Fitness to drive should be assessed on a case-by-case basis by the treating physician, and should not solely be based on a diagnosis of diabetes.
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C |
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Patients must be educated about risks associated with driving as well as appropriate precautions when driving as part of structured diabetes education
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C |
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Since the most significant factor associated with driving collisions appears to be a recent history of hypoglycaemia, drivers who experience a severe hypoglycaemic event (defined as an event requiring outside help, or resulting in loss of consciousness or seizure while driving) should ideally not drive until cleared by an appropriate medical practitioner
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C |
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If a severe hypoglycaemic event occurs, the person should not drive for a minimum period of six weeks thereafter, and only once hypoglycaemic awareness is re-established
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C |
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Health-care professionals should be aware of the medical standards for fitness to hold a driver’s licence
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C |
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People using insulin and/or insulin secretagogues must be counselled about the precautions to take for hypoglycaemia
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C |
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People with diabetes who are medically unfit to drive should be informed of their legal obligation, under the National Road Traffic Act, 93 of 1996, to inform the local Licensing Department of such. A family member of the patient should also be advised of this obligation
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C |
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Consider using glucose-lowering drugs with the lowest risk of hypoglycaemia in people who operate public transport and heavy-duty vehicles
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C |
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Visual acuity must be tested annually
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A |
INTRODUCTION
For many South Africans, driving is an essential part of daily living and is often a requirement of employment. Diabetes can affect driving performance because of chronic complications that impair sensory or motor functions (retinopathy, neuropathy, amputation, vascular disease), and because of transient cognitive dysfunction or loss of consciousness resulting from medication induced hypoglycaemia. The presence and extent of these factors vary from person to person, so the fitness of persons with diabetes to drive should be assessed on an individual basis.
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 driver’s license. The current evidence has recently been reviewed in detail in position statements from the American and Canadian Diabetes Associations.1,2
EFFECTS OF DIABETES ON ABILITY TO DRIVE
Diabetes impacts driving performance particularly when medication results in hypoglycaemia. There is less evidence that hyperglycaemia has major effects on driving. Furthermore, the chronic complications of diabetes such as retinopathy, cataracts and stroke may affect driving performance, as may associated conditions such as sleep apnoea. Hypoglycaemia may result in transient cognitive dysfunction or loss of consciousness which could impair driving ability.
Experimental laboratory studies and studies using a simulator have demonstrated that cognitive functions critical to driving (such as attention, reaction times and hand-eye coordination) are impaired during hypoglycaemia with driving performance adversely affected resulting in inappropriate speeding or braking, ignoring road signs and traffic lights and not keeping to traffic lanes.3,4
Diabetes and the risk of road traffic accidents
Overall, studies are inconsistent and there is no strong, epidemiological data that suggest an increase in traffic accidents among people with diabetes. A meta-analysis of 15 studies suggested that the relative risk of having a motor vehicle accident for people with diabetes i.e., without differentiating those with a significant risk from those with little or no risk, as compared with the general population ranges between 1.12 and 1.19, a 12–19% increased risk.5 Society tolerates much higher relative risks associated with a variety of other situations such as those with sleep apnoea, the very young driver, and drivers with attention deficit/hyperactivity disorder. It would thus be unjustified to restrict driving privileges of an entire class of individuals, such as drivers with diabetes.
Drivers managing their diabetes with insulin are the most significant subgroup of persons with diabetes, for whom a greater degree of restrictions is often applied across the rest of the world. Yet, when diabetes is controlled, insulin therapy per se has not been found to be associated with increased driving risk. The single most significant factor associated with driving collisions appears to be a recent history of hypoglycaemia.6,7
CURRENT LEGISLATION IN SOUTH AFRICA
Road user
All drivers who travel on public roads are subject to the requirements of the National Road Traffic Act, 93 of 1996 (RTA) in terms of ensuring their fitness to drive any vehicle (Sections 15 and 16), and in the event of an incident, to the consequences in terms of the offences and penalties contained in the Act. The current legislation in the RTA on Fitness to Drive states that a person shall be disqualified from obtaining or holding a learner’s and driver’s license “if he or she is suffering from uncontrolled diabetes mellitus.” This is, however, not defined further, nor is any mention made of the risks of therapy. Additionally, “sudden attacks of disabling giddiness or fainting” and “defective vision” could be relevant exclusion conditions for a patient with diabetes.
The Act currently puts the burden of proof on the individual, either during the application process or who should “within a period of 21 days after having so become aware of the disqualification submit the license to the MEC of the Province.”
There is currently no legal requirement for a health care worker to report patients deemed unfit to drive.
Unlike in many other countries in Europe and America, there is currently no separate legislation for drivers of commercial vehicles. Since commercial vehicle drivers drive for longer periods, at faster speeds, and on the highways more than average private drivers, and since commercial vehicles are larger and more lethal than private motor vehicles, or may be involved in public transportation, e.g. buses and mini-bus taxis, the potential for severe and disastrous traffic accidents is clearly of additional concern.
Employer Role
In South African Occupational Health and Safety Legislation there is a dual employee and employer responsibility. The Labour Relations and Employment Equity Acts guide stakeholders and decision makers in a fair and legal framework of “fitness to drive”. The employer is, in terms of the RTA, required to categorise all drivers according to the relative risks involved specific to their industry and according to the requirements for the issuing of the Professional Driving Permit. The employer must ensure that drivers undergo the necessary health evaluations as and when required. This must take place at the employer’s expense. The employer must provide the examining health professional with the necessary information on the driver’s category, special skills required and any known risk factors.
RECOMMENDATIONS FOR THE SOUTH AFRICAN SITUATION
General
The fitness to drive should be assessed on a case-by-case basis by the treating physician, and should not solely be based on a diagnosis of diabetes, but rather on unequivocal evidence of actual risk (Figure I). Health care professionals should be knowledgeable and regularly discuss ways to reduce the risks of driving with their diabetic patients. Persons with diabetes should take an active role in assessing their ability to drive and in obtaining information about recognition, treatment and avoidance of hypoglycaemia. Healthcare funders should recognise the recommendations for blood glucose monitoring in persons with diabetes who drive and provide adequate blood glucose test strips to cover additional testing before and during driving.
Table I: Medical standards for licensing1,2
- There is no recent history (generally at least 6 weeks) of a “severe hypoglycaemic event” (requiring assistance from another person)
- The driver experiences early warning symptoms (awareness) of hypoglycaemia
- The driver must demonstrate an understanding of the risks of hypoglycaemia and is following a treatment regimen that minimises the risk of hypoglycaemia
- There are no other potentially dangerous complications or comorbidities associated with diabetes, such as:
- Sight threatening retinopathy or cataracts (a complete eye examination by ophthalmologist or optometrist is mandatory)
- Obstructive sleep apnoea
- Unstable coronary artery disease or arrhythmias
- Transient ischaemic attacks
- Significant neurological deficits (e.g. cerebrovascular disease, peripheral or autonomic neuropathy).
Table II: Precautionary steps for drivers regarding hypoglycaemia
- Always carry your glucose meter and blood glucose strips with you
- Ensure that you have a glucose containing snack that is easily accessible in your vehicle
- Check your blood glucose no more than one hour before the start of the journey and every two hours during the journey, as reasonably practical
- Do not drive if blood glucose is at or less than 5 mmol/L
- Do not drive for more than two hours without considering having a snack. Do not drink alcohol before or while driving.
- Do not delay or miss a main meal
- Carry adequate glucose in the vehicle for self-treatment
- If experiencing hypoglycaemia, pull to the side of the road, turn off the engine and remove the keys from the ignition if safe to do so
- Check the blood glucose levels 15 minutes or more after the hypoglycaemia has been treated and ensuring it is above 5 mmol/L
- Do not drive until feeling well and until at least 30 minutes after the blood glucose is above 5 mmol/L
- Carry personal identification to indicate you have diabetes
Private vehicles
Persons with diabetes should have no restrictions to drive personal vehicles in general, irrespective of treatment regimen or diabetes type, but ideally require regular medical supervision and assessment (minimum two clinic visits per year). Physicians should look out for the high-risk patient and offer targeted education and advice. Patients who have experienced severe hypoglycaemic events or hypoglycaemic unawareness should consult with their health care providers to determine whether it is safe to drive and to implement interventions to avoid further episodes.
Commercial vehicles
Although South African law does not offer specific guidance, it would seem reasonable for physicians to give strong advice here. There should be clear guidance for conducting the annual assessment and specific criteria for holding a commercial license.
Candidates with diabetes who apply for commercial licenses should have an initial full medical assessment, as well as annual reassessment by a specialist physician, endocrinologist or family physician trained in diabetes management, including review of medical records and glucometer recordings of the previous 24 months.
In the interest of patient and public safety, it may be wise to consider using glucose-lowering drugs with the lowest risk of hypoglycaemia in people who operate public transport and heavy-duty vehicles.
CLINICAL ASSESSMENT
Clinical assessment should focus on identifying potentially at-risk drivers, with history focused on whether the driver has, within the past 12 months, experienced a severe hypoglycaemic event, has hypoglycaemic unawareness, or has comorbidities and complications of diabetes that may interfere with driving.8,9
Hypoglycaemia
Drivers who experience a “severe hypoglycaemic event” (defined as an event requiring external assistance, or resulting in loss of consciousness or seizure) while driving, should ideally not drive until cleared by a medical practitioner.
Assessment should focus on establishing the cause and future risks of hypoglycaemia. Patient education (Figure II) is imperative and medication changes may be required. Factors resulting in hypoglycaemia include amongst others non-adherence or alteration to medication, unexpected exertion, alcohol intake, or irregular meals. Meal regularity and variability in medication administration may be important considerations for long distance commercial driving or for drivers operating in shifts. Excessively tight control may contribute to hypoglycaemia.
Non-driving period after a ‘severe hypoglycaemic event’
If a severe hypoglycaemic event occurs, the person should not drive for a minimum period of six weeks thereafter. It takes many weeks for patterns of glucose control and behaviour to be re-established and for any temporary ‘reduced awareness of hypoglycaemia’ to resolve. The non-driving period should be individualised and will depend on factors such as identifying the reason for the episode, and the type of driving. Recommendation for return to driving should be based on patient behaviour and objective measures of glycaemic control (documented blood glucose) over a reasonable time interval.
Reduced awareness of hypoglycaemia
Reduced awareness of hypoglycaemia markedly increases the risk of a severe hypoglycaemic event and is therefore a risk for road safety. It may be screened for using the Clarke questionnaire10/a> which is particularly useful for people with insulin-treated diabetes of longer duration (more than 10 years), or following a severe hypoglycaemic event or after a crash.
Any driver who has a persistent reduced awareness of hypoglycaemia is not fit to drive unless their ability to experience early warning symptoms returns, or if they have an effective management strategy for lack of early warning symptoms.
Acute hyperglycaemia
While acute hyperglycaemia may affect some aspects of brain function, there is insufficient evidence to determine regular effects on driving performance and related crash risk. Each person with diabetes should be counselled about management of their diabetes during days when they are unwell and should be advised not to drive if they are acutely unwell with metabolically unstable diabetes.
Comorbidities and end-organ complications
Assessment and management of comorbidities is an important aspect of managing people with diabetes in respect to their fitness to drive. This should be part of routine review as per recommended practice and may include but is not limited to vision, neuropathy and foot care, neurological conditions, musculoskeletal conditions, sleep apnoea and cardiovascular conditions.
Author: Peter J Raubenheimer
Editors: Nazeer A Mohamed and Aslam Amod
References
1. ADA Position Statement. Diabetes and Driving. Diabetes Care 2014;37(S1):97-S103.
2. Diabetes and Driving: 2015 Canadian Diabetes Association Updated Recommendations for Private and Commercial Drivers. Houlden RJ, Berard L, Cheng A et al. Canadian J of Diabetes 2015;39:347-353
3. Cox DJ, Gonder-Frederick L, Kovatchev B, Jullian D, Clarke W. Driving decrements in type I diabetes during moderate hypoglycemia. Diabetes. 1993;42:239–43
4. CoxD, Gonder-FrederickL, KovatchevB, JulianD, ClarkeW. Progressive hypoglycemia’s impact on driving simulation performance. Occurrence, awareness and correction. Diabetes Care 2000; 23: 163-70.
5. ECRI Diabetes and Commercial Motor Vehicle Safety (Federal Motor Carrier Safety Administration). June 2011 Update. Plymouth Meeting, Pennsylvania, ECRI, 2011.
6. Laberge-Nadeau C, Dionne G, Ekoé JM, et al. Impact of diabetes on crash risks of truck-permit holders and commercial drivers. Diabetes Care 2000;23:612–617
7. Tregear SJ, Rizzo M, Tiller M, et al. Diabetes and motor vehicle crashes: a systematic evidence-based review and meta-analysis. In Proceedings of the Fourth International Driving Symposium on Human Factors in Driver Assessment, Training and Vehicle Design. Iowa City, Iowa, The University of Iowa, 2007, p. 343–35
8. National Transport System of Australia. Assessing Fitness to Drive 2016. https://static.diabetesaustralia.com.au/s/fileassets/diabetes-australia/17bc68dd-2414-496c-86fe-dcd5d689882e.pdf accessed 13 Feb 2017.
9. Diabetes Mellitus: Assessing Fitness to Drive. DVLA United Kingdom. March 2016. https://www.gov.uk/guidance/diabetes-mellitus-assessing-fitness-todrive. Accessed 13 Feb 2017.
10. Clarke W, Cox DJ, Gonder-Frederick LA, Julian D, Schlundt D, Polonsky W. Reduced awareness of hypoglycemia in adults with IDDM. Diabetes Care. 1995; 18(4): 517–522.