Type 2 diabetes is a chronic metabolic disorder caused by relative insensitivity to insulin combined with insufficient insulin secretion. It is characterised by high levels of blood glucose (hyperglycaemia). If prolonged, hyperglycaemia can cause microvascular and macrovascular damage. Improving blood glucose levels, blood pressure and lipid levels delays or prevents the complications of diabetes. Current practice aims to achieve a glycated haemoglobin (HbA1c) level of 6.5%, or 7.5% for those at risk of severe hypoglycaemia, although healthcare professionals appreciate that these targets will not be achieved by everyone. 

     

      The prevalence of diagnosed diabetes approximates 3.7% in England and 4.2% in Wales. This equates to more than 2 million people, of whom more than 85% have type 2 diabetes. Diabetes is estimated to account for at least 5% of healthcare expenditure in the UK, and up to 10% of hospital budgets. Type 2 diabetes usually occurs in people older than 40 years; however, it can occur earlier, particularly in people of South Asian or African-Caribbean origin. 

     

      Although lifestyle interventions (diet and physical activity) are the first-line treatments for the management of type 2 diabetes, most people subsequently need sequential addition of oral glucose-lowering drugs. Metformin is widely used as first-line oral therapy, with the sulfonylureas added as second-line therapy if glycaemic control remains poor or deteriorates. Other oral drugs for lowering blood glucose include alpha-glucosidase inhibitors, thiazolidinediones and meglitinides. Because type 2 diabetes is progressive, with secretion of insulin decreasing over time, most people with type 2 diabetes eventually need insulin. Healthcare professionals can prescribe a variety of formulations of insulin, including long- or short-acting formulations, or a pre-mixed (biphasic) combination of short- and long-acting insulins.