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   You are in: Home \ Living with Diabetes \ Driving and Diabetes
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Driving and Diabetes

Driving regulations in the UK.

New driving restrictions came into force in the UK on January 1st 1998 to bring the UK in line with the other European countries. There has been pressure to change these because of the adverse effects on people with diabetes who drive as part of their employment.

The legislation on January 1st 1998

From this date the new rules apply to EVERYONE when their licence is renewed. People with medically restricted licences, which includes people with insulin treated diabetes and about 10 other conditions, have been affected sooner because medically restricted licences are for a maximum of 3 years whereas normal licences that run to the age of 70.

Note: Diabetes is NOT specifically singled out the regulations apply to all conditions that require a medically restricted licence and everyone applying for a licence for the first time whether young or old, with a normal licence or a restricted licence, will come under these new rules.

Prior to January 1997 drivers who passed their CAR driving test were entitled, by this CAR licence, to also drive up to 16 seat minibuses (category D – not for hire or reward) and vehicles up to 7.5 tonnes (category C) and also to attach trailers to them. This has changed and from January 1st 1998 drivers must be able to meet higher medical standards in order to retain their entitlement to drive 16 seat minibuses and vehicles between 3.5 and 7.5 tonnes. These higher health standards are almost the same as those that apply to professional lorry drivers introduced in 1991. These recommendations were made on the advice of the Ministry of Transport’s Honorary Advisory Panel on the basis that:

·         the driving of heavier vehicles by people using insulin presents an unacceptable risk to other road users.

·         studies by experts on the consequences of insulin treatment show significant risk of hypoglycaemia which can lead to loss of consciousness or diminished judgement. Hypos without warnings can occur and a number of accidents have directly resulted from this.

The legislation means that:

You WILL be able to:

·         drive a car or vehicle up to 3.5 tonnes with a trailer

·         tow a caravan, boat, horse box or broken-down vehicle

·         drive a minibus of less than 9 seats

·         if you drive a non-commercial minibus on a voluntary unpaid basis you can apply for a special licence. This is bit complex and you can obtain information from the DVLA Swansea, Fact Sheet INF 28.

You will NOT be able to:

·         drive category C1 vehicles - lorries and light vans between 3.5 and 7.5 tonnes

·         drive category D minibuses between 9 and 16 seats except under certain circumstances (see Fact Sheet INF from the DVLA)

However there has been reconsideration of the position for C1 drivers - July 6th 1998

IDDT received a letter from the Minister of Transport:

"The original advice to the Honorary Advisory Panel on Driving and Diabetes was that there are no individual cases which can be regarded as sufficiently exceptional for concessions to be allowed. Nevertheless, the Panel’s conclusion differed from the views of the BDA and some physicians….I undertook to ask the Panel to examine this carefully and report to me with further advice.

The Panel now take the view that there is a case for changing the previous position, albeit in a limited way. They believe that subject to rigorous assessment a scheme to allow exceptional cases for existing C1and D1 licence holders could be devised for those who drive such vehicles for employment, which would minimise the risks to road safety."

Revised legislation

Good News for drivers of C1 Vehicles - March 2001

The government's public consultation about the decision to ban people with insulin treated diabetes from driving class C1 vehicles [small lorries and vans between 3,5 and 7.5 tonnes] ended on February 9th. And the result is:

From April 5th 2001

·         drivers who are treated with insulin will be assessed individually about their fitness to drive. A satisfactory annual medical check up and evidence of good diabetic control will be the main qualifying conditions.

·         The previous requirement to be employed to drive these vehicles and to have held a licence since before January 1997 has been removed.

·         The ban on D1 vehicles remains. (Minibuses with 9-16 passengers)

Note – the DVLA recommend that you do not apply or spend any money on a medical without first discussing the situation with your doctors.  

Driving Regulations for insulin treated people in Northern Ireland - August 2001

From August 20th 2001, people with diabetes treated with insulin will be allowed to drive Category C1 vehicles [large vans and lorries between 3.5 and 7.5 tonnes] after a satisfactory individual medical assessment and evidence of good diabetic control. DVLNI will issue information packs to drivers who feel that they will be able to benefit from these changes and new drivers will have the benefit of being assessed on an individual basis. 

The medical assessment - what does it mean?

A letter from Lord Whitty, Minister of Roads, to IDDT’s enquiry, cautioned that individual assessment would not necessarily lead to larger numbers of people being permitted to drive. However, he provided a list of the conditions that must be met t the medical assessment for driving C1 vehicles: 

'The applicant needs to satisfy the Secretary of State that since commencing treatment with insulin ‘he has had sufficient experience in the driving of vehicles to make practicable an assessment of the risk posed by his driving vehicles in those classes.’

The qualifying condition for this purpose was set to require that the applicant has driven at least 4 hours a day 3 days a week during the 12 month period prior to the application.

Applicants must have had no hypoglycaemia attacks while driving.

They must undergo an annual examination by a diabetes specialist to enable the DVLA to assess whether their condition is adequately controlled.

They must regularly monitor their condition and at least 2 months records will be required.

INSULIN AND DRIVING TAXIS
March 2007

The Department of Transport has issued new guidance for insulin users who hold licences for driving taxis. Up to now whether or not a taxi driver using insulin is allowed to drive a taxi has varied according to local authorities with some having automatic bans. IDDT is aware that some people with Type 2 diabetes have avoided going on to insulin in order to keep their taxi driving licence - not good for their long-term health but understandable when they have a family to support.

The new guidance for England and Wales published in October 2006 recommends that 'best practice is to apply the C1 standards'. CI licences are issued annually but only after applicants have successfully been through a strict medical assessment. Hopefully local authorities will now follow this guidance and the standards will not vary from one area to another and nor will people whose diabetic control is satisfactory be denied their livelihood. For taxi drivers who do receive an automatic ban, this new guidance can be used to argue their case.

Medical assessment forms - what the doctor says about you

People with diabetes frequently have to ask their doctor to fill in forms to independently assess their health and more specifically, their diabetes. The most common form is for driving licence renewal but there are others ones that occur from time to time – for suitability for employment, for insurance policies and for mortgage applications.

Diabetes Update Summer 2000, the Diabetes UK magazine for doctors and health professionals, includes a fact sheet advising doctors about the sort of information that he/she needs to fill in about their patients with diabetes and their diabetes. Perhaps we, as the patients, would also benefit from knowing the sort of information that is going to be provided about us once we have given written consent for this information to be passed on. So here are some of the points that doctors are being advised to make:

General Information

·         Type of diabetes, duration and treatment [insulin, tablets, diet only].

·         HbA1c results past and present.

·         Any episodes of ketoacidosis [very high blood sugars] or severe hyperglycaemia.

·         Hypos are a major concern for driving and for some employers.

·         Weight, vision [with glasses if worn], blood pressure, lipids and smoking habit.

·         Presence of diabetic complications – retinopathy, neuropathy and nephropathy.

·         The patient’s involvement in their own care eg their clinic attendance record, knowledge about diabetes etc.

·         The impact of diabetes on the ability to work or drive.

Employment

Decisions about the suitability for employment are made on two key points regardless of your diabetes and these are:

·         Are you fit to carry out the required tasks within the acceptable risks of the job?

·         Will the job itself adversely affect your health?  

If you are treated with insulin and work in potentially hazardous occupations you should realise that in assessing you for suitability for employment the doctor will be looking to see that:

·         You are physically and mentally fit – to non-diabetic standards.

·         Your diabetes is stable.

·         You have no disabling hypos and no loss of awareness of hypos

·         You have no advanced complications, no significant coronary heart disease or any other vascular disease.  

Hypoglycaemia

As we all know hypoglycaemia affects cognitive function and co-ordination and therefore is important for both work and driving. The DVLA requires specific information about hypoglycaemia and so your doctor will want to know from you and from your records, the following information:

·         Have you recently had any severe hypos?

·         If so, how many have there been in the last 12 months and the last 3 months and have they occurred during the day or the night?  

The fact sheet in Diabetes Update goes on to point out that while severe hypos can occur in anyone with insulin treated diabetes, recurrent severe hypos suggest that there is impaired hypo warnings and that this is a major driving hazard. For this purpose the article defines severe hypoglycaemia as a hypo which requires the help of someone else regardless of whether or not the person with diabetes is conscious or unconscious. It goes on to point out that:

It is inappropriate for people with recent severe hypoglycaemia to drive, to work in dangerous environments or to undertake hazardous tasks and that there should be an interval of perhaps 6 months without a severe hypo. 

Loss of hypo warnings

If you have loss of hypo warnings, you should not drive or work in a dangerous situation, because not only could this be dangerous for you but it could also harm others. IDDT has always said that people who have lost or partially lost their warnings do not necessarily know that they have. So what are the signs that loss of hypo warnings may have occurred?

·         Frequent severe hypos reduce warnings and even one mild hypo is enough to reduce them.

·         If your hypo warnings are sweating, shaking trembling, then you are likely to have sufficient warnings, but if your warnings are confusion, slurred speech and difficulty walking or functioning in other ways, then you are likely to have impaired hypo warnings.

·         If your spouse or partner recognises that you are hypo before you do.

·         Regular blood glucose levels below 3mmols/l without symptoms.

·         A ‘good’ HbA1c result ie within the normal range could mean that there have been hypos that haven’t been recognised – unawareness.  

We have to remember that when a doctor signs forms on our behalf he/she is taking responsibility for saying we are able to carry out the employment tasks or drive a vehicle safely. It is right and proper therefore that all these questions have to be addressed by the doctor and that he/she is not just making life difficult for us!

Hypoglycaemia and driving.

The change in the regulations for C1 and D1 categories is largely based on the possibility of hypos occurring whilst driving. The presence of hypo warnings and the ability to recognise them is very important if people with diabetes are to be safe drivers. This is a concern for people with diabetes who drive any vehicle.

Statistics

·         Statistically people with diabetes have no more accidents that people without diabetes.

·         But of 2000 accidents caused by collapse at the wheel, 340 of the people had diabetes. [Ref 1]

·         Total hypo unawareness involves only 1-2% of the diabetic population but up to one third report intermittent problems in recognising hypoglycaemia. [Ref 2]

Ref 1 Managing the hypoglycaemic driver: Journal of Diabetes Nursing Vol 1 No 4 1997

Ref 2 The relationship between symptomatic and biochemical hypoglycaemia in IDDM patients: Journal of Int Med 228; 642-6 

Tips for safe driving:

·         Always drive with glucose or sweets to hand – not in the glove compartment.

·         Blood test regularly, especially on long journeys.

·         If you feel a hypo coming on, pull off the road, get out of the car or move into the back seat. (So that you are obviously seen not to be driving the car if the police should come along.)

·         Treat the emergency hypo immediately and then drive on and stop for a proper meal.

·         Consider raising the blood glucose levels a little while driving.

·         Remember that following a hypo your judgements may be impaired for an hour afterwards even though you feel OK and your blood glucose levels are back to ‘normal’.

Remember that diagnosis of diabetes which is treated with insulin or tablets means that you must inform both the DVLA and your motor insurers that you have been diagnosed with diabetes. This is a material change in your circumstances and failure to inform could result in prosecution and your insurance being invalid.

Driving and loss of warnings of hypoglycaemia

In October 2002, IDDT received a letter from Jo Taylor whose husband was killed in a motor accident by a driver with diabetes who went hypo at the wheel. He was acquitted of dangerous driving because he had a hypo at the time. Jo has stressed that she does not want to tar everyone with diabetes with the same brush but she does want to prevent other people from suffering as she and her family have done and to raise awareness of the need for blood glucose testing before driving.

But it really is not as simple as that, as we all know. Blood testing itself does not stop you going hypo, it tells you what your blood sugars are at that moment in time so that you can eat if necessary. Many of us equally know that they can drop quite quickly, especially under a stressful situation – the M6 on a Friday afternoon! So it is essential to be vigilant all the time and to test before driving and at frequent intervals on a long journey. But the real problem when driving is loss of hypo warnings, reduced warnings or sometimes you have warnings and sometimes you don’t. Loss of hypo warnings or reduced warnings is dangerous and if this is the case, then driving should cease.

Statistics not dubious!

Details of Jo’s case were published in the magazine of Diabetes UK, Balance, Sept/Oct 2002. But the article failed to point out that the driver’s doctor gave evidence that he did not tell his patients to blood test before driving and that education of doctors as well as patients is clearly essential. The article also said “There were also some rather dubious statistics given [in the newspapers] for the number of hypos people with diabetes have, which tended to exaggerate the dangers associated with driving when you have diabetes.”

This last comment brought in a sharp response in the next Balance from Secretary and Chairman of the government’s Medical Advisory Panel on Driving and Diabetes.

The statistics are not dubious at all:

·         The DVLA receive on average 12-15 police notifications per month relating to significant driving incidents associated with hypoglycaemia at the wheel from a driving population of about 100,000 drivers with insulin treated diabetes. [This does not include those not reported to the police!]

·         In the past 12 months, the DVLA has been made aware of at least 5 fatalities in hypoglycaemia-related traffic accidents.

·         Hypoglycaemia is not a major contributor to the overall number of road traffic accidents, it is a potentially preventable cause of serious road accidents and/or fatalities and if hypo awareness is lost or diminished, then patients should be advised to cease driving.

Driving and diabetes poses conflicts – a member writes:

“People with insulin dependent diabetes who want to keep their driving licences may feel that any disclosure to their GP or consultant about hypos could affect the renewal of their licence. There have been times in the past when I would very much have liked to discuss problems with hypos with my doctors but disclosure may have jeopardised my driving licence and so my livelihood.

I am sure that most people with diabetes take sensible and appropriate precautions when driving. But being placed in this situation where discussions of hypos may lead to the doctor having to inform the DVLA of hypos, means that we are probably not receiving help and advice from them that we need so we are not receiving the help we need to improve the situation. I can see the sense in both the DVLA questionnaire about hypos and the need for disclosure but we do seem to be in a vicious circle. If we have hypos and tell the truth, then we risk losing our driving licences but if we don’t seek the advice of our doctors on how to try to prevent these, then nothing will change.”

This highlights the very real conflicts that arise – the doctor is the person from whom we need help to try to resolve the problems with hypos but he/she is also the person that says ‘yes’ or ‘no’ to our driving licence renewal. Unless we resolve this conflict so that patients feel able to discuss with their doctors ways of trying to avoid hypos and/or regain their hypo warnings, then the risks of traffic accidents will continue.

“Good control is not just the avoidance of hyperglycaemia but also the avoidance of hypoglycaemia.”

This statement was made by Professor Stephanie Amiel at IDDT’s annual meeting some years ago but it is one that perhaps we all need to remember, patients, doctors and healthcare professionals.

The achievement of ‘excellent’ HbA1cs may be at the expense of increased frequency of hypos and this in itself increases the risk of loss of warnings, as Prof Amiel’s own research has shown. We have to remember that the HBA1c test does not measure low blood sugars, only the high’s so a good result could mean that there are frequent undetected mild/moderate hypos.

Diabetes poses many conflicts and driving is certainly one of them:

·         the conflict between ‘good’ control that reduces the risk of long-term complications but increases the risk of hypos and perhaps relaxing control a little to avoid hypos.

·         the conflict of quality of life now against the unknown quality of life in the future if blood sugar levels are relaxed.

The effect of loss of driving licence should not be underestimated in terms of quality of life – it can affect self-esteem, jobs, income and pleasure and therefore the quality of life of the whole family.

Driving warnings in insulin products

In 1998 the driving warnings in insulin product information were reviewed in the UK and Europe and after consultation, the following amendments were made:

Summary of product characteristics in the Data Sheets

"The patient’s ability to concentrate and react may be impaired as a result of hypoglycaemia or hyperglycaemia. This may constitute a risk in situations where their abilities are of special importance (eg driving a car or operating machinery.)

Patients should be advised to take precautions to avoid hypoglycaemia whilst driving, this is particularly important for those who have reduced or absent awareness of the warning signs of hypoglycaemia. The advisability of driving should be considered in these circumstances."

Patient Information Leaflet

"Your ability to concentrate or react may be reduced if you have hypoglycaemia or hyperglycaemia. Please keep these possible problems in mind in all situations where you might put yourself or others at risk (eg driving a car or operating machinery.)

You should contact your doctor about the advisability of driving if you have:

·         frequent episodes of hypoglycaemia

·         reduced or absent warning signs of hypoglycaemia."

Driving and medicines.

Walking the straight line
Some police authorities are re-introducing the old test of having to walk the straight line for motorists that are stopped for driving offences. The widespread use of breath testing has largely stopped the need for this test for people driving under the influence of alcohol but this means that people driving under the influence of drugs, whether medicines or illegal substances, may be slipping through the net.

Facts

·         The link between alcohol and road traffic accidents is well established.

·         There is increasing evidence that some prescribed medicines and some over-the-counter medicines may also impair driving ability.

·         A recent survey has shown that 17% of drivers involved in road traffic accidents were found to have traces of medicines in their blood eg antidepressants and antihistamines.

The commonly used medicines that may impair your ability to drive are those that may cause drowsiness are:

·         Some antidepressants

·         Strong pain killers eg codeine

·         Powerful tranquillisers eg those used for the treatment of some types of mental illness

·         Some medicines used to treat epilepsy eg phenobarbitone

·         Benzodiazepine tranquillisers used to treat anxiety and insomnia

·         Some antihistamines for treatment of hayfever and allergies

Your ability to drive may also be impaired by:

·         Eye drops that cause blurred vision

·         Insulin and some oral anti-diabetic medicines that may cause confusion as a result of low blood glucose levels.

How do you know if your medication may impair your ability to drive?

All medicines that may cause drowsiness are labelled with this warning:

"Warning. May cause drowsiness. If affected do not drive or operate machinery."

It is important to note the words ‘if affected’ in this warning because it means that it places the responsibility on you to decide whether or not the side effects of drowsiness are likely to impair your driving ability. In other words, you have been warned so if you had an accident as a result of being drowsy, then the responsibility rests with you!

If alcohol is taken with some medicines, then this can make the drowsiness worse and so labels may also contain the warning:

"Avoid alcoholic drink."

A clear message:

Always read the information leaflet about any medications you take whether prescribed by your doctor or bought over the counter at your pharmacy. You can obtain further information about your medicine from:

·         Your doctor

·         Your pharmacist

·         The Medicines Helpline on telephone 0345 573410

Driving and visual field

IDDT’s July 2002 Newsletter drew attention to the DVLA implementing more stringent standards for visual field assessment and driving. This has resulted in greater numbers of people losing their driving licence because of reduced visual fields after laser treatment for retinopathy. IDDT has written to the DVLA for clarification on this matter.

Jackie Banks had laser treatment for her retinopathy 25 years ago and there was no need for further treatment. She has been classed as fit to drive ever since - that is until these stringent regulations came into effect. She has almost led a one-woman campaign for the last 3years which has resulted in her retaining her licence as well as helping many other people to do the same.  

The seriousness of the new regulations was brought home to us when IDDT member Stephen, applied to renew his driving licence as a matter of routine and he visited a DVLA nominated optometrist for a field test. Then like a bolt from the blue, a letter arrived from the DVLA informing him that he could no longer drive because of his visual field loss. Stephen had laser treatment some years ago but his retinopathy was non-progressive and in the opinion of his ophthalmologist, had never interfered with his visual fields to prevent him driving. So what had changed - certainly not the state of Stephen’s eyes, at his last routine check with his ophthalmologist. The answer – the system!

The visual field test

Visual field are measured on instruments called perimeters and there are two types:

·A manually operated perimeter eg Goldmann using a system on moving lights.

·An automated perimeter that uses static flashing lights and automatically prints out the results. This is widely used because it requires less skill on the part of the operator.

The manually operated Goldmann type is often easier to use for the person being checked and may well give better results. Clearly your results could be different according to which perimeter is used. The results of these tests will influence the renewal of your licence.

DVLA regulations
These are very difficult to interpret, even for qualified people. There are several problems with this system that we have raised with the DVLA:

·         perimeters were never designed to be a definitive test on which to base such vital decisions.

·         The DVLA has commissioned research to look at the best way of testing for visual field defects and driving which will be available in 2-3years time. We have therefore queried the appropriateness of this stringent interpretation of the EU Directive BEFORE the results of the research are known.

·         The DVLA perimeter uses a static fixation point ie your eye has to be fixed on a central point while trying to recognise the flashing lights in the peripheral field. Actually no one drives like this, the eyes are moving all the time and therefore minor defects in the peripheral field are not noticed because of the eye movements.

The response from the DVLA:
As simply as I can put it, the DVLA only accept the results of automated perimeters and not the Goldmann. However, where there is some doubt as to the width of the visual field, then they may request a further test on a Goldmann to ‘avoid erroneously refusing or revoking the entitlement’ to drive. However, they also acknowledge that the automated perimeter was recommended as the standard for consistency of quality of testing and accessibility, ie the ability of the tester and the fact that not many optometrists possess a manually operated perimeter. Is this a good enough reason for choosing one particular instrument, the Goldmann, the results of which could affect the lives of so many people, especially when the research has not been completed yet?

Application for renewal of driving licence

·         In the past, a report from your own ophthalmologist was sufficient information for the DVLA but now many people are being required to attend a DVLA nominated optometrist [optician] for a field test, apparently to speed up the process. The optometrist’s report goes to the DVLA and they make the decision.

·         IDDT is aware that in some cases, the visual field test is not carried out by the optometrist but by an ‘operative’ in the shop and we have reported this to the DVLA. When the future of your licence is at stake, my advice to readers is that you ensure that the test is carried out by the nominated optometrist, who actually receives the fee for this anyway, NOT by an unqualified person.

·         It is important to note that if you have recently seen your ophthalmologist for your routine visit, then you can request that his/her report is sent to the DVLA and so avoid using the optometrist system. In my view, this is preferable because not only is your history is known but hospitals will have both types of perimeters. My advice would be to try to organise your routine eye check within weeks of your licence being up for renewal. This requires a bit of forward planning but it may be worth it.

So what happened to Stephen?

On receipt of the letter from the DVLA, he immediately went to see his ophthalmologist who was very supportive and confirmed that his visual fields had not deteriorated over the years since his laser treatment. He carried out field tests with BOTH types of perimeters and Stephen appealed against the decision to revoke his licence. Several months later he received his new driving licence. But in the meantime, he had to have taxis to work everyday because he starts early in the morning and he had several months of unnecessary stress and worry to say nothing of the inconvenience and costs. Other people have not been so fortunate. Clearly if there is significant visual field loss, then it is unsafe to drive but if the loss is borderline by the DVLA standards, then it is important to be aware that you do not simply give up.

But it looks as if this situation may improve………..
DVLA Expert Consensus Workshop, March 2006

This workshop made various recommendations that have yet to be adopted officially but if you are facing this situation it is well worth using them in the meantime. The new recommendations show greater understanding that [a] retinopathy is not always progressive and can stabilise and [b] that some people can learn to adapt to field loss without being unsafe drivers. If/when adopted this will ensure that people are treated more fairly than in the past.

The recommendations state:

·         Before having the Esterman field test, you should be given full information on the procedure and appeals system. You should also be familiarised with the Esterman test before taking it and if you fail, you should be offered a repeat test on the same day.

·         If you fail the Esterman test you could be offered a Goldmann test [a different instrument].

·         If you fail the Goldmann test but you could show that you meet the criteria to be considered an exceptional case, you could be allowed to re-apply and have the chance to demonstrate that you have compensated sufficiently for your field loss by taking an on-road driving assessment. To be classed as an 'exceptional case' you would need to supply a medical opinion that your condition has stabilised and that you have learned to compensate sufficiently for your field loss.

·         These alternatives should be made available so that people do not have their driving licences removed unnecessarily. However the burden of proof in showing that the retinopathy has stabilised rests with the person and not the DVLA.

·         Visual fields should not be re-tested for at least 3 months after laser treatment as vision may be affected immediately after it.

·         The current 3 yearly visual field testing may be too frequent for some people where there is evidence of a stable condition and a mechanism would need to be in place to identify the people where this applies.

There is a need for more evidence and further research.

Note: It appears that other EU countries have not adopted the same stringent interpretation of the EU Directive as the UK [what’s new?]. In most EU countries, it is the ophthalmic consultant that tells people whether or not they should be driving following laser treatment. 

Research

ALCOHOL, DRIVING AND HYPOGLYCAEMIA
Alcohol can interfere with all aspects of the normal physiological, cognitive and symptomatic responses to hypoglycaemia. In otherwise healthy individuals, the net effect of alcohol on glucose metabolism is neutral, provided that liver glycogen stores are replete. For insulin treated people, the influence of hypoglycaemia is more relevant.

A study conducted in 1990 found that moderate alcohol consumption of 100-120mg/100ml blood,* markedly reduced awareness of hypoglycaemia and slowed down reaction time. The loss of awareness occurred despite the presence of the usual symptoms such as facial flushing, blurred vision, pounding heart and sweating. The patients felt hypo after alcohol when blood alcohol levels were within the normal range but by contrast, the clinical features of low blood glucose can be mistaken for alcohol intoxication.

Even at very low levels of blood alcohol it is possible that there may be a deleterious effect on cognitive performance which may be aggravated if blood glucose levels fall below the threshold which has been shown to impair cognitive performance. It is therefore better not to take any risks with driving and better not to drink at all if driving.

* Current legislation in the UK provides an upper limit of 80mg/100ml blood.

[Kerr et al, Diabetologia 33: 216-21] 

IMPACT OF DIABETES ON CRASH RISKS OF TRUCK-PERMIT HOLDERS AND COMMERCIAL DRIVERS
The US the Federal Highway Administration has prevented people who use insulin from driving commercial vehicles. However, it has temporarily waived commercial restrictions for some insulin treated people providing they met certain medical standards. In Canada from 1987 people with Type 2 diabetes and some exceptional cases with Type 1 diabetes have been permitted to derive trucks under certain conditions but not buses minibuses or emergency vehicles. But the US Federal Highway Administration is no longer giving waivers, despite little scientific evidence to support this decision.

An analysis of crash risks among diabetic truck-permit holders was carried out in Quebec by looking at the records of 13,453 permit holders between 1987 and 1990. People with Type1 and Type 2 diabetes were involved because treatment of Type 2 with sulphonylureas can cause hypoglycaemia. Additional health information was obtained and a telephone survey was conducted to collect information on driving patterns and exposure. This applied to people driving Class 1 [articulated trucks] and Class 3 [single unit trucks] looking at 3 groups – those with complications, those without complications and those treated with insulin.

It is important, however, in assessing the results to take into account the fact that there are fewer professional drivers in both articulated and single unit truck classes with diabetes with complications and considerably fewer taking insulin.

The results were as follows:

·         articulated truck drivers - the 3 groups with diabetes did not differ in their risk ratio for crashes from the healthy group.

·         single unit truck drivers - the people with diabetes without complications had a higher risk ratio of crashes and this applied to people with the same diabetic condition in this group both Types1 and 2. This is an important because it includes people with Type 2 diabetes not treated with insulin, 76% of them being treated with tablets.

The authors off possible explanations of higher risk ratios for single unit truck drivers:

·         The first and most obvious is that drivers of articulated trucks are subject to more stringent medical requirements then single unit truck drivers and therefore are selected out initially. The crash risks may also be underestimated because of self- selection with the more severely affected people choosing not to drive or to restrict their driving.

·         The work environment for single unit truck drivers seems more stressful – they are more likely to be driving on busy urban streets with parking difficulties than are articulated truck drivers and have a tighter time schedule.

·         They spend more time handing goods and have a less regimented work situation than articulated truck drivers.

For all these reasons, the authors recommend that the results warrant further investigation and that the apparently non-significant differences in healthy groups and articulated truck drivers should not be regarded as reason for relaxing the current medical restrictions.

Diabetes Care [Vol 23: No 5 May2000] 

THE PERCEPTION OF SAFE DRIVING ABILITY DURING HYPOGLYCAMIA IN PATIENTS WITH THYPE 1 DIABETES
Hypoglycaemia and its subsequent cognitive impairment may place people with diabetes at risk when driving. This study looks at the factors that influence judgements of safe driving ability during hypoglycaemia.

30 men and 30 women who had an average duration of IDDM of 9 years and no complications underwent hypoglycaemia with a stepped insulin clamp. Glucose levels were reduced in stages over 190 minutes to 40mg/dL [2.2mmols/l]. At each point the patients completed a symptom questionnaire and a neuropsychological test, estimated their blood glucose level and reported whether they could drive safely. The study was repeated with another 93 patients later in the year and the results were similar.

The proportion of patients judging that they could drive safely decreased as blood glucose levels went down from 70% at 120mg/dL [6.6mmols/l] to 22% at 40mg/dL [2.2mmols/l]. When blood sugars were between 3.3 and 3.9mmols/l the first group said they would drive 60% of the time and the second group 64% of the time. With a blood sugar of less than 2.2 mmols/l the figures were 38% and 47%.

Men and middle-aged patients were more likely to consider it safe to drive during hypoglycaemia than women and those under 25 years. Those who were symptomatic and those who recognised hypoglycaemia were less likely to report ability to drive during hypoglycaemia. Most patients who were cognitively impaired appeared to recognise this and reported that they could not drive safely at blood glucose levels of 40mg/dL [2.2mmols/l]. Glucose levels less than 70mg/dL [3.9mmols/l] should be treated before driving. This information is as important for middle-aged, experienced drivers as it is for younger inexperienced drivers.

The author is quoted in the Pharmaceutical Journal 28.8.99 "Given the relatively low level of low blood glucose detection, the suggestion that individuals measure their blood glucose levels and raise potentially low blood glucose levels before driving does not seem unreasonable."

Am J Med 1999 Sep; 107(3):246-53  

MEDICAL RESTRICTIONS TO DRIVING: THE AWARENESS OF PATIENTS AND DOCTORS
This study was set up to look at the awareness of elderly patients and medical doctors of medical restrictions to driving. Separate questionnaires were completed by 150 elderly patients and 50 doctors [all grades] and all were interviewed face to face without prior warning. The results showed that only 21 patients were current drivers but 6 of them should not have been driving. While 103 patients considered themselves eligible to drive, 46 had medical restrictions to driving. Doctors’ knowledge of current licensing policy and action to be taken if a patient was not eligible to drive was poor. Knowledge of medical restrictions to driving was scanty with few doctors giving the correct driving restrictions for the five specific conditions [which includes diabetes]. The researchers recommend that education of doctors about medical restrictions to driving should begin at an undergraduate level and continue throughout their postgraduate career.

Postgrad Med J 1999 Sep;75[887]:537-9 

WORK DISABILITY AND DIABETES
This study was carried out in the USA to look at the working patterns and work time lost in people with diabetes. It was part of a large population based survey of people 25 years and older. Work disability was defined as self-reporting of being unable to attend work due to illness or disability for more than 2 quarters of 1987. Of the 1,502 people with diabetes 25.6% reported work disability compared with 7.8% of those without diabetes. These rates were higher for older people, women and African Americans. People with diabetes had more days off work but had similarly hourly wages. Predicted average earnings were significantly lower for people with diabetes at all ages. The authors recommend that there needs to be a closer examination of the causes of time off work for those with diabetes.

Diabetes Care 1999; 22: 1105-1109
 

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