Insulin dosing and outcomes among commercially insured patients with type 2 diabetes in the United States

The purpose of this study was to examine costs, resource use, adherence, and hypoglycemic events among patients with type 2 diabetes mellitus (T2DM) treated with increasing doses of 100-U/mL (U-100) insulin regimens.

Data from Truven's Health Analytics Commercial Claims and Encounters database from January 1, 2008, through January 31, 2011, were used. Regressions were used to examine the associations among costs, resource use, adherence, and receipt of a hypoglycemic event and index dose of insulin. Specifically, general linear models with a γ-distribution and log link were used to examine costs, whereas logistic and negative binomial regressions were used to examine resource use and hypoglycemic events. All analyses controlled for patient characteristics, preindex comorbidities, general health, use of antidiabetic medications, and visits to an endocrinologist.

The study focused on 101,728 individuals with T2DM who received an outpatient prescription for U-100 insulin. In general, costs and resource use are highest among patients treated with the highest dose of insulin (>300 U/d). For example, all-cause and diabetes-related hospitalizations and office visits were highest in the highest-dose cohort. Costs generally followed the same pattern. Patients who were prescribed the lowest dose of insulin (10-100 U/d) generally had higher all-cause or diabetes-related inpatient and emergency department costs and resource use compared with those patients with an index dose >100 to 150, >150 to 200, and >200 to 300 U/d. There were generally no significant differences in rates of hypoglycemic events based on index dose.

These results suggest significant differences in patient outcomes based on dosing of insulin. Those patients with T2DM using insulin at the highest and lowest dose ranges have the highest costs and resource use.