Optimization of insulin therapy in patients with type 2 diabetes mellitus: beyond basal insulin

To describe patients with Type 2 diabetes mellitus treated with basal insulin, with or without oral antidiabetics in UK primary care, and evaluate insulin treatment patterns and factors explaining changes in therapy.

Retrospective analysis of patients with Type 2 diabetes within The Health Improvement Network UK primary care database. Patients receiving basal insulin between January and June 2006 were followed until July 2009.

Analysis included 3185 patients, mean age 65.6 years [standard deviation (SD) 12.4], 50.9% men, median diabetes duration 9.6 years, median basal insulin use 1.3 years, 86.5% had received oral antidiabetics in the previous 12 months. Mean follow-up was 2.9 years (SD 1.0), 59.8% patients maintained basal insulin throughout follow-up with a mean HbA(1C) of 69 mmol/mol (SD 19; 8.4%, SD 1.7) at baseline and 65 mmol/mol (SD 17; 8.1%, SD 1.6) during follow-up. During follow-up, 6.9% of patients discontinued, 19.3% intensified with and 14.1% switched to prandial or premixed insulin. Patients who intensified (prandial) had a mean HbA(1c) of 77 mmol/mol (SD 18; 9.2%, SD 1.6) before change and a mean HbA(1c) of 71 mmol/mol (SD 21; 8.6%, SD 2.0) at the end of the study. Those switching to premixed insulin had a mean HbA(1c) of 80 mmol/mol (SD 18; 9.5%, SD 1.7) before change and a mean HbA(1c) of 69 mmol/mol (SD 17; 8.5%, SD 1.5) at the end of the study. Increasing HbA(1c) and longer diabetes duration explained intensification and switch.

The majority of patients had HbA(1c) above the 53 mmol/mol (< 7%) target at baseline and post-intensification/switch. The HbA(1c) levels were reduced by intensification/switch suggesting that insulin changes did have some impact. Most patients did not change insulin treatment despite having higher than recommended HbA(1c) levels. Reasons for not changing treatment in face of unsatisfactory clinical outcomes are unclear. Further research is warranted to explore barriers towards therapy change.