Essay: What is Diabetes and how can this condition impact on driving ability.

Introduction
In this assignment I will aim to increase my knowledge and level of understanding of Diabetes and the potential impact this may have on driving skills.
I will use a case study of a recent client to provide a framework for my critical review of my current practice and use research to support my own learning needs which will enable me to consider and develop future best practice.
I am an Occupational Therapist with a background predominantly working in the National Health Service (NHS). I have been working as an Occupational Therapist for just over 20 years and have worked in both the hospital and community settings. I have experienced working with a variety of clients with differing medical and health issues. I joined East Anglian Driveability (EAD) in 2017 and have quickly had to adapt to a different way of working. In undertaking my current assessments, I realised that I no longer had a significant period of time to build therapeutic relationships with my clients and learn about their conditions. Within my other roles I was able to develop these relationships over a period of time. I also worked with very specific client groups depending on the area or job role I was in. Within my current role I am presented with different medical conditions on a daily basis with little pre-assessment information, often these clients have multiple medical conditions associated or secondary to their primary condition. On reflection, in my first few months in the job I found it very difficult to manage all the information I was presented with and gain an understanding of how certain medical conditions may impact on a person’s ability to drive safely. I had a very basic awareness of what conditions were notifiable to the Driving Vehicle licencing Agency (DVLA). This often led to me feeling ‘out of my depth’ and as a result I had to critically reflect on my practice and skills as an assessor. I feel as health professionals engaging with and reflecting on how our experiences affects us is an invaluable tool, and by learning from our own emotional responses to certain situations’ helps us improve our future practices.
The case study I have chosen to reflect upon was a defining moment for me, as following the assessment I felt there were significant gaps in my knowledge base around diabetes as a condition; and in particular the effects of hypoglycaemia on driving skills which required further research. I aim to use this assignment as a method to further my knowledge and support other colleagues with recommendations for best practice. The client who for the purpose of this assignment will be referred to as Mrs D.
Mrs D is a 36-year-old lady and referred herself to EAD as she felt her medical condition was beginning to have an impact on her ability to drive using standard foot controls. She has been driving for many years; however, now mainly undertakes more local journeys taking her young children to school. She had completed a pre-assessment questionnaire which gave some information about her medical condition and the current difficulties she was experiencing. Mrs D has Type 1 diabetes which she has had from birth. On her questionnaire she indicated that she is beginning to experience peripheral neuropathy. She also has diabetic retinopathy which is currently stable.
The assessment was conducted by myself and a driving assessor and comprised of initial interview, full physical assessment, some components of the Rookwood Driving Battery (McKenna, 2009), static rig, visual screening and on-road assessment.
Mrs D was able to give a very good history of her condition, she participated fully in conversation and had and good level of insight into the current difficulties she was experiencing. I would in the majority of cases complete a full cognitive assessment using the Rookwood Driving Battery (Mckenna, 2009) however, I felt that this was not necessary, due to information I had gleaned from her during initial interview. I completed specific cognitive tasks to demonstrate level of executive function.
Following the physical assessment her main difficulties related to altered sensation and sensory loss in both legs; with poor coordination particularly in her right leg.
In the United Kingdom (UK) there are 3.7 million people who have been diagnosed with Diabetes and a further approximately 1 million with type 2 diabetes who have yet to be diagnosed. This equates to 90% with type 2 diabetes and 10% with type 1. It is estimated that if significant changes are not made by 2025 more than 5 million people will be diagnosed with Diabetes (Diabetes UK, 2018).
In the world the number of individuals with diabetes has increased from 108 million (1980) to 422 million recorded in 2014. In 2016 it was estimated that it is the seventh leading cause of death and that half the number of deaths were associated with high blood glucose levels which occurred before the age of 70 (World Health Organisation, 2018).
There are several different types of diabetes, however, for the purpose of this assignment I will mainly be focusing on the more common types 1 and 2. Type 1 diabetes is often associated with children, as it is generally diagnosed at around the age of 10-14. However, type 1 can be diagnosed at any age. If diagnosed later in adults over 35 it can sometimes be referred to as Latent Autoimmune Diabetes of adulthood. Type 1 diabetes is classed as an autoimmune disease whereby the insulin producing beta cells located in the pancreas are destroyed. As a result, the body is unable to produce enough insulin (hormone) to sufficiently regulate the blood glucose levels.
There is no clear evidence of the exact cause of type 1 diabetes with several theories suggesting a genetic predisposition or environmental factor such as a viral infection. (Diabetes.co,uk, 2018). It can be treated with insulin which can be administered via different methods. This type of diabetes requires regular blood glucose monitoring with a blood glucose monitor and this is an essential part of managing diabetes. The National institute for Health and Care Excellence (NICE) guidelines recommend regular HbA1c (glycated haemoglobin) checks every 3-6 months, and although target ranges for blood sugars vary for each individual, a general guide is 5-7 mmol/l on waking (fasting level), 4-7 mmol/l before meals at other times of the day and 5-9mmol/l 90 minutes following a meal. (NICE, 2016)
Type 2 diabetes is a metabolic disorder whereby the body is unable to metabolise glucose and can lead to hyperglycaemia (high blood sugar levels). This is a result of the body being unable to either produce enough insulin or not being effective in utilising the insulin produced. It is linked to weight and occurs generally in individuals over 40 however, can be diagnosed at any time. Treatment for type 2 diabetes may focus on changes in lifestyle through diet and exercise which may be sufficient to manage or set diabetes into a state of remission; particularly when diagnosed and treated at an early stage. This early education and management may prevent pre-diabetes developing into type 2. For more advanced cases antidiabetic medication and insulin may be required to manage blood glucose levels. (Diabetes UK, 2017).
Management of both Type 1 and Type 2 diabetes focus on improving blood glucose control, either through medications (Appendix 1) and recommendations for lifestyle changes with regards to healthy eating and regular exercise. NICE have set out clear quality care standards for adults with diabetes. There is a great focus on providing patient education models which include structured education programs on carbohydrate intake and insulin. The Dose adjustment for Normal eating (DAFNE) is offered to commissioners enabling patients to self-manage their disease through the use of a skill-based programme. This programme has shown to improve blood glucose control and reduce the risk of severe hypoglycaemia. (DAFNE study group, 2002)
There are long term complications associated with both type 1 and type 2 diabetes if blood glucose levels are not maintained at recommended levels, these include retinopathy, neuropathy, kidney disease, cardiovascular disease and stroke.
Mrs D had informed us of her retinal neuropathy (currently stable) during the initial interview and I was aware from my own knowledge of the potential impact of diabetes on vision. During the assessment visual spatial tasks were completed and visual acuity checks carried out in line with the DVLA, (2018) which state an individual,
“Must be able to read (with glasses or contact lenses) a car number plate from 20 metres”
“Must meet the minimum eyesight standard for driving by having a visual acuity of at least decimal 0.5 (6/12) measured on the Snellen scale (with glasses or contact lenses, if necessary) using both eyes together or, if you only have sight in one eye only, in that eye”.
Diabetic retinopathy is the main cause of blindness in the UK among adults 20-74 and causes twenty thousand cases of blindness each year. Glaucoma, corneal disease and cataracts are also commonly seen with individuals with diabetes. The potential impact of this on visual acuity and visual field deficits can translate into difficulties in adapting to speeds of traffic, short following distances, difficulties maintaining road position and negotiating corners. Problems may be encountered with night driving or driving in some adverse weather conditions due to glare or contrast sensitivity (Hunter, De Vries & Brown 2009). Mrs D demonstrated that she was able to meet the required visual legal standards for driving and completed all visuospatial perceptual tasks to a good standard.
Mrs D experiences peripheral neuropathy and associated pain from this, Scheiner, (2011) documented “60-70 % of all people with diabetes will develop some form of nerve damage in their lifetime, most develop a form called peripheral neuropathy. Neuropathy is considered the most common complication associated with both type 1 and type 2 diabetes. The prevalence in patients with chronic disease is greater than 50% and approximately 8% in newly diagnosed patients. (Boulton, et al., 2005)
There has been very little research conducted on lower extremity neuropathy on driving performance. However, Meyr & Spiess, (2017) looked at brake response times for type 2 diabetic drivers with lower limb neuropathy and found that 37.8 % demonstrated a slower brake response time and an increased frequency of abnormally delayed brake responses; this would translate to a “response difference distance of 17 ft for 2 vehicles travelling at 55 mph”. Mrs D demonstrated slightly slower reactions times averaging just over one second on the static rig, this combined with increased nerve pain and impaired proprioception enabled us to explore alternative driving solutions, and hand controls were identified as the safest option for her.
Driving is a multifactorial complex task requiring the interaction of cognitive, motor and visual skills. The complications of diabetes can potentially have a significant impact on a person’s ability to drive safely. These complications include visual changes, neuropathy, and some cognitive processes as a result of hypoglycaemia which can be a side effect of insulin and sulfonylurea therapy. (Watson, Currie, Lemon, & Gold, 2007). The potential effects and impact of hypoglycaemia on driving ability has been well studied as this is considered the principle safety concern effecting diabetic drivers treated with insulin.
Studies have shown that hypoglycaemia has an effect on some cognitive – motor processes as well as highlighting the increased metabolic demands of driving which may contribute to hypoglycaemia. Participating in driving can also cause stress and this physiological arousal can sometimes be mistaken as the onset of hypoglycaemia (Cox, Gonder-Frederick, Kovatchev, & Clarke, 2002).
Hanson, et al., (2017) and Graveling, Warren, & Frier, (2004) have conducted studies to show that acute hypoglycaemia has a significant impact on learning and many high-level cognitive functions particularly planning. Sommerfield, Dreary, McAulay, & Frier, (2003) reported that all memory systems but in particular working and delayed memory were affected during acute hypoglycaemia. There is also a significant deterioration in attentional functioning and flexibility as well as visual and auditory attention, during acute hypoglycaemia (McAulay, Dreary, Sommerfield, & Frier, 2005).
There are not a significant number of recent studies available that show the effects of hypoglycaemia on visual processing, however, Ewing, Dreary, Mccrimmon, Strachan, & Frier, (1998) conducted research on a relatively small sample size of sixteen adults, all subjects demonstrated normal visual acuity and no other diabetic complications such as retinopathy. The results suggested that hypoglycaemia had no effect on the conventional test for visual acuity however, identified impairment in general cognitive function test (trial making B and digit symbol test). Of the three visual tests carried out there was no change in visual movement detection, but significant results for contrast sensitivity and visual change detection, suggesting a direct effect of a hypoglycaemic episode on visual processing, concluding that hypoglycaemia can impair visual perception when driving.
Frier, Wright, & Dreary, (2009) studied the effect of insulin induced hypoglycaemia on spatial abilities and this was shown to cause significant reduction in most spatial cognitive abilities as well as deterioration of speed of processing.
The effects of hypoglycaemia and recovery times of cognitive function following hypoglycaemia vary however, some individuals may experience a delay in recovery of impaired cognitive performance up to 75 minutes (Zammitt, Warren, Dreary, & Frier, 2008). This would suggest that impact and recovery times associated with the disruption of these cognitive process will have a significant impact on an individual’s ability to drive, and therefore recommendations are that a driver should wait until 45 minutes after euglycemia (normal blood sugar levels) has been re-established.
Many studies have been carried out looking into the increased risk of road traffic accidents occurring with people with insulin treated diabetes however, results have been conflicting and widely debated. One study carried out by Cox, et al., (2003) identified that Type 1 diabetic drivers have an increased risk of driving mishaps however, type 2 treated with insulin tended not to be of a higher risk than the non-diabetic community. Concluding that clinical and treatment factors such as more frequent episodes of hypoglycaemia, method of insulin delivery and less frequent self-testing before driving appeared to be attributable to the increase of driving mishaps in type 1 individuals.
A study carried out by Cox, Gonder-Frederick, Kovatchev, Julian, & Clarke, (2000) looked at progressive hypoglycaemia’s impact on driving simulator performance with 37 adults and found that performance begins to deteriorate when blood sugar levels fall below 3.8 mmol/l. Many of the subjects were slow in responding to this and taking corrective actions. Only one in three subjects self-treated however, this was not until blood glucose levels had fallen below 2.8 mmol/l. Cox et al (2000) reported “The longer treatment is delayed, the greater the neuroglycopenia, which precludes corrective behaviours” and that “drivers should treat themselves while driving as soon as low BG/Impaired driving is suspected and should not begin driving when their BG is in the 5.0-4.0 mmol/l range without prophylactic treatment”.
The study demonstrated at these low blood glucose levels some elements of driving skills were affected, difficulties were seen with speed regulation either driving too fast or too slowly, driving off the road or crossing the central line, inappropriate braking, ignoring road signs and traffic lights. Fewer than 25 % were aware of any driving performance impairment, suggesting that driving performance at relatively mild hypoglycaemia can be significantly disrupted. This study also highlighted that those with hypoglycaemia unawareness, which is when individuals do not receive any warning symptoms that blood glucose levels are low may make unreliable decisions about when it is safe to drive as 43% of subjects with hypoglycaemia unawareness reported they would drive whilst hypoglycaemic as opposed to only 4% with normal hypoglycaemia awareness. Therefore, as Cox et al (2000) discussed “Prevention of hypoglycaemia-related driving crashes relies on both a driver’s ability to recognise his/her driving impairments and then immediately taking the corrective actions”.
Cox, et al., (2009) conducted a prospective study to identify driving mishaps among 452 individuals with type 1 diabetes, these recordings included minor mishaps and near misses and recorded incidences of mild and severe hypoglycaemia whilst driving. The results identified 52% of those drivers had at least one driving mishap over a 12-month period, with 32% experiencing two or more and 5% reporting six or more events. 35% of individuals who experienced a driving incident tested their blood glucose level within 30 minutes of starting the journey and of those 78% had a blood glucose level under 5.0 mmol/l.
Lonnen, Powell, Taylor, Shore, & Macload, (2008) argue that insulin use does not pose an increased risk to road safety with their results highlighting overall accident rate was1469 per 100 000 (non-diabetic population) vs. 856 per 100 00 diabetic population. Their research strongly supports the need for an individual approach and risk assessment to be adopted when imposing driving restrictions for insulin treated diabetics. However, the reliability of this study has been questioned by Major, Rees, & Frier, (2009) with regards to the studies population age, the assumption that people with diabetes hold a valid licence in the same proportion of non-diabetic population, and the effects of other long-term complications which may affect fitness to drive. Major, Rees, & Frier, (2009) on behalf of the DVLA in their response to this study stated,
“whilst undoubtably the 3-year medical review that is required for licence renewal will remove a proportion of those at highest risk, the DVLA continues to receive nearly 30 police notifications per month of serious incidents and accidents related to hypoglycaemia whilst driving”.
However, due to the identified potential risk of a road traffic accident occurring due to a hypoglycaemic episode, this has led to many countries placing certain restrictions on the driving licences for drivers with diabetes. With a distinction between those who received insulin therapy and those that do not. In the UK the DVLA provides guidance and statutory regulations for individuals who require insulin to manage their diabetes. DVLA (2018) state that Group 1 drivers must inform them if they “Suffer more than one episode of severe hypoglycaemia while awake within the last 12 months” they define severe glycaemia as “needing the assistance of another person”. Having frequent sleep hypoglycaemic episodes are considered no longer relevant for licensing purposes. Individuals must also notify the DVLA if the have a severe hypoglycaemic episode whilst driving. For Group 2 drivers DVLA state they “must stop driving vehicles of this category and must notify the DVLA if you have a single episode of hypoglycaemia requiring the assistance of another person, even if this occurred during sleep”
Group 1 drivers must also notify the DVLA if they develop impaired awareness of hypoglycaemia and for Group 2 drivers if they have any degree of impaired awareness. The DVLA have produced a leaflet (INF188/2) which helps individuals understand their obligations with regards to when to notify them and provides information on the warning signs which may lead to a hypoglycaemic episode, these signs include sweating, shaking, heart palpitations, feeling hungry or thirsty and feelings of anxiety. If these early symptoms are not treated then this may lead to symptoms of confusion, concentration difficulties, slurred speech, irrational behaviour and eventually have the potential for loss of consciousness (DVLA, 2018). This again highlights that even some of the early symptoms if left untreated can have a significant impact on an individual’s ability to drive safely.
. Watson, Currie, Lemon, & Gold, (2007) delivered a questionnaire to 117 diabetic patients treated with insulin attending diabetic clinics and 106 health care professional (HCP) to establish if there was a good awareness for the statutory regulations and safe practice as specified by the DVLA. 95% of patients were aware they should notify the DVLA. Only 15% of patients always tested their blood glucose level prior to driving with 24% never testing and only 17% would wait the recommended 45 minutes after a hypoglycaemic episode.
From research it would appear that I am not alone in my level of knowledge with regards to current legislation. Watson et al., (2007) study identified 62% of HCP’s knew that patients needed to check blood glucose levels prior to every journey, however, 17% thought this to be only the case if a journey was to be more than two hours. 70% were aware that a patient should wait at least 45 minutes after a hypoglycaemic episode before returning to drive. 8% did not know that level of awareness of hypoglycaemia may be a contraindication for driving. In a New Zealand study only 28% of insulin-treated diabetic drivers reported receiving education by a health professional about safe driving practices. (Bell, Huddart, & Krebs, 2010).