Many people may not realise that developing either type 1 or type 2 diabetes can also affect their performance behind the wheel. Stephanie Fsadni gets the lowdown from the first local study on the subject.
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A significant proportion of local insulin-treated drivers have a poor understanding of the perils of hypoglycaemia, a study by two local medics reveals.
“Hypoglycaemia can cause car crashes and may constitute a public health hazard,” says Sandro Vella, who conducted the research with Mario J. Cachia. Both are consultant physicians, diabetologists and endocrinologists at Mater Dei Hospital.
The EU has, in fact, adopted stringent regulations in this regard, and these have been adopted by Maltese law. However, the study shows that awareness about the dangers of hypoglycaemia is still low.
Cognitive functions that are critical to driving, such as attention, visual information processing, reaction times and hand-eye coordination are impaired by the condition, even if mildly
The term refers to low levels of circulating blood glucose and is a feared and relatively common complication of insulin therapy in patients with type 1 and type 2 diabetes.
Normal brain function depends on a continuous supply of glucose and thus, hypoglycaemia is particularly perilous in the setting of motor vehicle driving.
“Cognitive functions that are critical to driving, such as attention, visual information processing, reaction times and hand-eye coordination are impaired by the condition, even if mildly,” says Dr Vella.
Hypoglycaemia and Driving – An Audit of Insulin-Treated Maltese Diabetes Drivers is the first local study on the subject. It was carried out among patients attending the Diabetes and Endocrine Centre at St Luke’s and Mater Dei Hospitals between 2006 and 2008.
The 115 participants were asked to answer a detailed questionnaire provided they had been treated with insulin for at least one year, had a current driving licence, had driven within the preceding year and intended to drive in the future.
Among the outcomes of the study, 2.8 per cent of drivers admitted to having been involved in a motor vehicle accident due to hypoglycaemia, but none was major.
Dr Vella refers to a 2004 Scottish study by Frier et al that reported a similar rate of motor vehicle accidents attributed to hypoglycaemia (3.5 per cent).
A more worrying find, according to Dr Vella, is that 32 per cent of patients reported sustaining a self-treated hypoglycaemic event while driving during the previous year. Similarly, five per cent of patients replied that they had sustained a hypoglycaemic event that required assistance.
However, despite these figures, few respondents claimed to take the necessary precautions, such as carrying a blood glucose meter and carbohydrate sources.
A majority (64.9 per cent) admitted they never carry a blood glucose meter when driving and, even though 70.5 per cent said they always carry a carbohydrate source, Dr Vella says that ideally all diabetic patients treated with insulin or sulphonylureas (an oral glucose-lowering agent prone to induce hypoglycaemia) should do this.
Also, 45.1 per cent of drivers said they would stop driving to treat hypoglycaemia and rest for at least 30 minutes (suggested time is 45 minutes) but 46.1 per cent of drivers said they would drive off immediately after correcting hypoglycaemia.
All this goes to show that education on the subject is inadequate. The researchers, therefore, plan to launch an extensive media campaign and work on improving patients’ knowledge on the subject. They also intend to re-audit the situation in a few years’ time.
“In my opinion, this data also makes a case for more widespread availability of glucose meters, glucose test strips and long-acting insulin analogues (a more modern type of insulin therapy),” Dr Vella concludes.
Facts and figures
■ Hypoglycaemia often impairs successful and satisfactory attainment of adequate glucose control that, among other measures, is essential to avert several diabetes-related complications.
■ Hypoglycaemia mainly results as a consequence of the limitations of insulin delivery systems, resulting in inappropriately high-circulating insulin concentrations between meals and at night. This commonly complicates exercise, excessive insulin dosing or missed meals.
■ The incidence of severe hypoglycaemia is about 20 per cent per year in patients with type 1 diabetes within a few years of diagnosis, but increases to 50 per cent in patients with long-standing disease.
■ The incidence in type 2 diabetes patients treated with glucose-lowering agents (sulphonylureas) stands at around seven per cent, which is comparable to those who have recently started taking insulin. However, type 2 diabetes is 10 times more common than type 1.
■ Hypoglycaemia may also affect cognitive function, such as attention and visual information processing.
■ Full recovery of cognitive function after an incident of hypoglycaemia may not occur until 45 minutes have elapsed from restoration of euglycaemia (normal glucose concentrations).
■ Increased duration of diabetes, as well as previous episodes of hypoglycaemia, may impair the body’s defence mechanisms, rendering patients unaware of such an adverse event (hypoglycaemia unawareness), and thus at an increased risk of sustaining further episodes of hypoglycaemia.