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The legal requirements for diabetes and driving are outlined in the Waka Kotahi (New Zealand Transport Authority) guidelines – please refer.
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The following includes important points relevant to type 2 diabetes including mandatory requirements and factors to consider.
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Current Waka Kotahi (New Zealand Transport Authority/NZTA) guidelines recommend that annual assessment is required for class 2,3,4 and 5 licence applications or P,V,I or O endorsements for all people with type 2 diabetes on insulin and/or sulfonylureas. All assessments for type 2 diabetes and assessments for class 1 licences for people with type 1 diabetes can now be performed by GPs and nurse practitioners in primary care. A specialist assessment is now only mandatory for commercial classes and endorsements for people with type 1 diabetes. But, in addition to endocrinologists and physicians specialising in diabetes, the latter assessments can now be done by nurse practitioners and nurse specialists working in specialist diabetes services.
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The main factors to consider for fitness to drive are:
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Risk of hypoglycaemia (only relevant if on insulin and/or sulfonylureas)
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Risk is low if episodes of hypoglycaemia are rare, there is no hypoglycaemic unawareness and people regularly monitor their glucose levels (especially around driving)
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Risk is also reduced by a regular pattern of shifts with adequate meal breaks
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Severity of diabetic complications including any:
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Impaired vision from diabetic eye disease
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Cataracts and previous panretinal photocoagulation may disproportionately affect night vision
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Reduced ability to safely feel or operate the pedals from diabetic neuropathy and peripheral vascular disease
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Risk from ischaemic heart disease and cerebrovascular disease
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Common comorbidities such as obstructive sleep apnoea and any associated daytime somnolence, or cognitive impairment
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Any other factors that may impair safety of driving
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NB: There is no HbA1c cut-off for licencing because HbA1c is a poor indicator of risk for fitness to drive. This is because the risk of hypoglycaemia or complication burden cannot be determined from a single HbA1c and there is no evidence that hyperglycaemia alone impairs driving safety. However:
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People with high glucose levels who feel unwell should be encouraged not to drive
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Drivers with an HbA1c above target should still have their glucose lowering therapies escalated appropriately
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Insulin and sulfonylureas can be safely used in occupational drivers but adequate monitoring is essential
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Consider use of CGM and maximising non-insulin/sulfonylurea glucose lowering therapies first
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People on insulin and sulfonylureas should be made aware of the legal requirements around diabetes and driving:
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Their glucose levels need to be > 4.2 mmol/L before they drive (often easier to say ‘above 5 safe to drive or above 5 to stay alive’).
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They should also be advised to:
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Stop driving and to check their glucose levels every 2-3 hours on long trips or immediately if symptoms of hypoglycaemia
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Ensure their glucometer or CGM and treatment for hypoglycaemia is available at all times
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People must not drive for one hour after an episode of mild hypoglycaemia (< 4 mmol/L) and not for 24 hours after an episode of insulin-induced severe hypoglycaemia (requiring assistance) or 48 hours after an episode of sulfonylurea-induced severe hypoglycaemia.
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People who have an episode of severe hypoglycaemia whilst driving cannot drive for 1 month.
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Remedial action and specialist review is almost always required in this scenario before a person can return to drive.
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Specialist review is no longer mandatory for any assessment of driving licences or endorsements in people with type 2 diabetes but consider if :
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Hypoglycaemic unawareness with ongoing hypoglycaemia
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Severe hypoglycaemia whilst driving
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Frequent episodes of mild hypoglycaemia
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Any other doubts over the patient’s ability to drive e.g. degree of peripheral neuropathy