Hypoglycaemia in Type 2 diabetes

Abstract

The primary cause of hypoglycaemia in Type 2 diabetes is diabetes medication-in particular, those which raise insulin levels independently of blood glucose, such as sulphonylureas (SUs) and exogenous insulin. The risk of hypoglycaemia is increased in older patients, those with longer diabetes duration, lesser insulin reserve and perhaps in the drive for strict glycaemic control. Differing definitions, data collection methods, drug type/regimen and patient populations make comparing rates of hypoglycaemia difficult. It is clear that patients taking insulin have the highest rates of self-reported severe hypoglycaemia (25% in patients who have been taking insulin for > 5 years). SUs are associated with significantly lower rates of severe hypoglycaemia. However, large numbers of patients take SUs in the UK, and it is estimated that each year > 5000 patients will experience a severe event caused by their SU therapy which will require emergency intervention. Hypoglycaemia has substantial clinical impact, in terms of mortality, morbidity and quality of life. The cost implications of severe episodes-both direct hospital costs and indirect costs-are considerable: it is estimated that each hospital admission for severe hypoglycaemia costs around pound1000. Hypoglycaemia and fear of hypoglycaemia limit the ability of current diabetes medications to achieve and maintain optimal levels of glycaemic control. Newer therapies, which focus on the incretin axis, may carry a lower risk of hypoglycaemia. Their use, and more prudent use of older therapies with low risk of hypoglycaemia, may help patients achieve improved glucose control for longer, and reduce the risk of diabetic complications.

FIGURE 1

The effect of duration of diabetes on the proportion of patients experiencing severe hypoglycaemic episodes. The open circles represent patients in the intensive arm in the United Kingdom Prospective Diabetes Study (UKPDS) and show an increase in the proportion of patients experiencing a severe hypoglycaemic event over time. In contrast the closed circles represent patients in the diet-only arm of UKPDS and do not show an increase [21]. Reprinted from The Lancet, 352: UKPDS 33. Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes, 837–853, Copyright 1998, with permission from Elsevier.

FIGURE 2

Proportion of patients with Type 2 and Type 1 diabetes of differing durations and receiving different regimens experiencing at least one severe hypoglycaemic attack during 9–12 months’ follow-up. All patients were receiving insulin except the group treated with sulphonylurea [35]. Reproduced from [35] with kind permission of Springer Science and Business Media.