Objective: Most patients with type 2 diabetes eventually require exogenous insulin therapy to achieve good glycemic control due to the progressive nature of the disease. Insulin aspart is a rapid-acting insulin analog developed for prandial use. This study aimed to illustrate the implications on healthcare costs of adding insulin aspart to basal therapy in a real-world setting.
Methods: Patients with type 2 diabetes who intensified previous basal therapy with insulin aspart were identified from a large commercial US healthcare data source between April 2007 and September 2008. Patients were required to have received basal insulin treatment with or without concomitant oral antidiabetic (OAD) therapy for at least 90 days pre- and post-initiation of insulin aspart. Wilcoxon signed-rank test and McNemar's test were used for continuous and categorical variables, respectively, to analyze the difference of self-comparison between pre- and post insulin aspart add-on.
Results: In total, 1,739 patients with an average age of 56 years were identified, of whom 55% were male. After initiation of insulin aspart, a significant improvement in glycemic control was observed (change in HbA(1c): -0.5%, p=0.0013). Similarly, a reduction of 0.4% in HbA(1c) was observed for the subpopulation of 151 patients, who had both pre-and post-index HbA(1c) data (p=0.0085). Also, significantly fewer patients used OADs after insulin aspart initiation (56 vs. 64%, p< 0.0001). Overall and diabetes-related healthcare costs also significantly decreased by $2,283 and $2,028, respectively (p≤ 0.0001). Diabetes-related inpatient visits appear to be the main contributor to total cost (46%); however, after initiation of insulin aspart the number of inpatient visits decreased by 0.50 visits/patient/year (p< 0.05). This decrease was reflected in a large reduction in cost related to inpatient visits ($3,019/patient).
Limitations: A regression to the mean effect may be associated with this pre-post comparison. The ability to make conclusions regarding cause and effect may be limited due to the retrospective design of this study.
Conclusions: Patients with type 2 diabetes achieved better glycemic control and needed less OAD treatment after adding insulin aspart to previous basal therapy. Furthermore, patients experienced on average reduced healthcare utilization after initiation of insulin aspart, which resulted in significant cost savings.