Some patients may feel that health care professionals are more concerned about normalization of blood glucose concentration than the occasional hypoglycaemic episode. But for the person who has diabetes, hypoglycaemia can be a terrifying experience to be avoided at all costs. To this end the person may aim for persistent hyperglycaemia, preferring the absence of hypoglycaemia now to the vague and distant threat of long-term tissue damage. Many older patients still cling to the old advice to 'keep a little sugar in your urine'. The professionals who are most likely to brush aside anxieties about hypoglycaemia are those who have never experienced it themselves, or have, so far, not encountered a hypoglycaemic patient who has had an accident or caused one.
The price of normoglycaemia is often hypoglycaemia. Doctors should watch that their zealous quest for a normal glucose to reduce the likelihood of tissue damage does not create problems for their patients.
Joseph always kept his blood glucose between 4 and 6 mmol/l by careful control of his diet and his insulin. He went on an outdoor activity course. Like everyone else unaccustomed to outdoor activities he was given detailed advice to eat more and to reduce his insulin to avoid hypoglycaemia. He agreed. On day 1 he was hypoglycaemic while climbing. He was told to reduce his insulin further and the dietitian reiterated advice to eat more at mealtimes and snacks. Next day he lost consciousness and had to be revived with glucose. The group then revealed that Joseph had been leaving his food at meal times, and had been seen throwing his snack away. Joseph subsequently admitted that he had not reduced his insulin at all. When asked why, he said that his doctor had told him he would go blind if his glucose went above 6 mmol/l.
Approximately a third of people with insulin-treated diabetes will experience hypoglycaemic coma; 2-3 per cent of insulin-treated patients have frequent severe hypoglycaemia.
Hypoglycaemia used to be considered rare in sulphonylurea-treated patients but with the current focus on normoglycaemia this is no longer the case: about a third of patients on glibenclamide experience hypoglycaemia. Patients taking metformin alone are rarely at risk of hypoglycaemia unless the metformin is taken in overdose.
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