OBJECTIVES: Cardiovascular disease is the major cause of death in patients with type 2 diabetes (T2DM) and long-term follow-up from UKPDS showed improved glycaemic control was associated with risk reduction for both myocardial infarction and death.  The objective of this study was to quantify the expected difference in long-term outcomes associated with blood glucose treated to target compared with levels observed in clinical practice. METHODS: Data from UK primary care (THIN) were used to obtain the demographic and risk factor profiles of patients initiating monotherapy, dual therapy, and insulin-based therapy between 2005 and 2009.  The Cardiff Type 2 Diabetes Model was initiated with cohort profiles consistent with those subjects initiating monotherapy, and HbA1c change over time was implemented under three scenarios: (1) HbA1c maintained at 6.5%; (2) therapy escalation occurring at a threshold of 7.5%, and (3) therapy escalation occurring at mean HbA1c levels observed in clinical practice. A 40-year time horizon using was used with UK £ 2011 costs; both costs and benefits were discounted at 3.5%. RESULTS: Data were available for 35,330 subjects; mean HbA1c (change) at therapy initiation for mono, dual, and insulin therapy was 8.0% (-0.93%, p<0.001), 8.5% (-1.1%, p<0.001), and 9.8% (-1.47%, p<0.001), respectively.  Under scenario 1, total predicted costs (TC), life expectancy (LE), and quality-adjusted life-years (QALYs) were £7,200, 16.4 years, and 13.7 QALYs, respectively.  For scenario 2, TC, LE, and QALYs were £14,416, 15.9 years, and 13.2 QALYs, respectively, whereas for scenario 3, TC increased to £14,914, while LE and QALYs decreased to 15.6 years and 12.8 QALYs, respectively. CONCLUSIONS: Failure to achieve glycaemic goals results in decreased life and quality adjusted life expectancy and excessive healthcare costs.  Given current budgetary constraints, an ageing population, and increasing obesity, it is imperative that patients with T2DM are optimally managed in routine clinical practice.