Real world outcomes of adding rapid-acting insulin versus switching to analog premix insulin among US patients with type 2 diabetes treated with insulin glargine

INTRODUCTION Patients with type 2 diabetes mellitus (T2DM) often require intensification of basal insulin therapy. This retrospective, observational study compared real-world outcomes in US patients with T2DM treated with insulin glargine who added a rapid-acting insulin (RAI) (basal-bolus approach) with those who switched to premixed insulin (PMX). METHODS The national US IMPACT® database was used to identify data from adult patients (≥18 years of age) with T2DM who added bolus RAI to insulin glargine (GLA + RAI) or who switched from GLA to PMX between 2001 and 2009. A stringent 1:1 propensity score-matching method was used to address the selection bias by matching GLA + RAI patients and PMX patients. Clinical and economic outcomes were determined for 1 year after the initial pharmacy claim for RAI or for PMX. Outcomes included treatment persistence and adherence, average insulin doses, glycated hemoglobin (A1C) levels, the prevalence and incidence of hypoglycemia, and health care costs/utilization. Analysis was carried out using an intent-to-treat approach. RESULTS The study included data from 746 propensity-matched patients (n = 373 in each cohort). Treatment persistence and adherence were higher in the GLA + RAI cohort. There was no significant difference in A1C reduction from baseline and the number of patients achieving target A1C levels of <7% in each cohort. The incidence of hypoglycemic events was also similar in both groups. However, during follow-up, many patients (48.8%) who initially switched from insulin glargine to PMX crossed back over to use GLA and/or RAI as part of their regimen. Health care costs and utilization levels were not significantly different. CONCLUSION Clinical and economic outcomes were similar in T2DM patients who added RAI to GLA and in those who switched to PMX, but a basal-bolus strategy appears to be associated with better treatment persistence and adherence.