Abstract

Type 2 diabetes is defined by chronic hyperglycaemia, decreased insulin secretion and increased insulin resistance and is often associated with overweight or obesity, hypertension and dyslipidaemia.¹ Aims of treatment include minimising long-term complications (e.g. cardiovascular disease, blindness, chronic kidney disease, premature mortality) and avoiding unwanted effects of treatment (e.g. severe hypoglycaemia, weight gain).¹ Publication of the United Kingdom Prospective Diabetes Study (UKPDS) 33 study in 1998 suggested that ‘intensive blood glucose control’ to lower the glycated haemoglobin (HbA_1c) in people with type 2 diabetes reduced microvascular disease but not macrovascular complications.² The UKPDS 34 study in overweight patients found that metformin produced less of a reduction in HbA_1c but reduced cardiovascular complications and death.³ More recently, further trials have examined the impact of intensive glycaemic control and have produced conflicting results.^1,4–11 Here we examine the evidence and guideline recommendations for HbA_1c targets; glycaemic control for acutely unwell patients and targets in pregnancy will not be covered.