Clinical Outcomes After Insulin Initiation in Patients with Type 2 Diabetes: 24-Month Results from INSTIGATE

Introduction To examine changes in insulin regimens and glycemic control during the 24 months after initiation of insulin in patients with type 2 diabetes mellitus. Methods Data were collected over a 24-month period from patients requiring insulin initiation as part of usual care, in a prospective, observational study. Changes in insulin regimens and hemoglobin A1c (HbA1c) were examined within countries (Germany, Greece, Spain) and overall. Results Prandial insulin only was most commonly initiated in Germany, while basal or premixed formulations were initiated in Greece and Spain. In Germany, compared with Greece or Spain, the patients were slightly younger and had a shorter diabetes duration when initiating insulin. For patients overall, 76.1% did not change their insulin regimen between initiation and 24 months. The most obvious change was a shift from prandial to basal/bolus in Germany, with almost doubling of mean daily insulin dose; in Greece and Spain, more patients stopped using insulin and the trend to more complex regimens was not seen. Overall, mean (SD) HbA1c decreased from baseline (9.4 [1.7]%) to 6 months (7.2 [1.0]%), but with little further change through 24 months (7.2 [1.1]%). HbA1c change with basal/bolus insulin (−2.6 [2.0]%, baseline 10.1%) was greater than with basal only (−2.0 [1.8]%, baseline 9.3%). Mean HbA1c less than 7% was achieved and maintained over 24 months in Germany, but was not achieved at any time in Greece or Spain. Conclusions Within 24 months of insulin initiation, the majority of patients with type 2 diabetes remained on the same insulin regimen initially instigated, despite the well-established progressive loss of prandial and basal endogenous insulin secretion. Adequate glycemic control was best achieved where insulin dosage adjustments and insulin intensification took place.