Abstract
Objectives: Outcomes in patients with type 2 diabetes may vary depending on the antidiabetic medication used. Observational studies of outcomes of diabetes pharmacotherapy are needed to understand the implications of choice of controller in different populations. This study compared differences in total health care costs, medication adherence, and persistence in patients with type 2 diabetes enrolled in the North Carolina Medicaid Program that were newly started on thiazolidinedione (TZD) therapy with patients starting other oral antidiabetics during the same period. In addition differences among the TZDs with respect to these outcomes were examined.
Methods: A total of 1774 patients newly starting TZD therapy between July 2001 and June 2002 were compared to 1709 patients starting other oral antidiabetic medication (metformin or sulfonylureas) for health care costs and outcomes in the post-medication start year. In addition, a sub-group analysis of health care costs in patients starting either TZD (pioglitazone [n = 1086] versus rosiglitazone [N = 688]) was compared. All included patients had complete enrollment for the 24 months of follow-up. Multivariate techniques incorporating health care utilization in the year prior to start of new therapy were utilized to determine the cost impact of one therapy versus another.
Results: Results of multiple regression analyses suggest that patients starting TZD have better treatment adherence and persistence in the post-medication start year compared to patients starting other oral antidiabetics (13% increase in Medication Possession Ratios, and 10% increase in therapy persistence index, both p < 0.001). In addition, patients starting TZDs had 16.1% lower total annual health care costs ( p < 0.01) compared to patients starting other oral antidiabetics. There were no differences in adherence and cost outcomes between the 2 TZDs.
Conclusions: Introduction of thiazolidinedione therapy in a Medicaid-enrolled type 2 diabetic population was associated with significantly improved treatment adherence, persistence, and lower annual health care costs in the post-start year compared to patients starting other oral antidiabetics.