Trends of antidiabetic drug use in adult type 2 diabetes in Korea in 2002–2013: Nationwide population-based cohort study

This study investigated trends in the prescription of antidiabetic medications for patients with type 2 diabetes, focusing on changing patterns of prescriptions and the cost of drugs during the last 10 years. Retrospective data on patients with type 2 diabetes aged 30 years or older were analyzed using information from the National Health Information Database collected by the National Health Insurance Service in Korea from January 2002 to December 2013. We identified patients with type 2 diabetes who had at least one service claim in each year during the study period. The prescribing information was collected and fixed-dose combination tablets were counted as each of their constituent classes. The total number of adults with type 2 diabetes who were treated using antidiabetic agents increased from 0.87 million in 2002 to 2.72 million in 2013 in Korea. Among antidiabetic medications in 2002, sulfonylurea (SU) was the most commonly used agent (87.2%), and metformin was the second (52.9%). However, in 2013, the use of metformin increased to 80.4% of the total antidiabetic prescriptions. The use of dipeptidyl peptidase-4 (DPP-4) inhibitor increased remarkably after release in late 2008 and composed one-third of the market share with 1 million prescriptions (38.4%) in 2013. Among the prescriptions for monotherapy, only 13.0% were metformin in 2002, but the amount increased to 53.2% by 2013. In contrast, the use of SU declined dramatically from 75.2% in 2002 to 30.6% in 2013. Dual and triple combinations steadily increased from 35.0% and 6.6% in 2002 to 44.9% and 15.5% in 2013, respectively. In 2013, SU with metformin (41.7%) and metformin with DPP-4 inhibitor (32.5%) combination were most frequently prescribed. The total antidiabetic medication cost increased explosively from U.S. $70 million (82.5 billion won) in 2002 to U.S. $4 billion (480 billion won) in 2013. The use of antidiabetic agents and their costs have been increasing steadily. Metformin is the most commonly used drug recently. The use of DPP-4 inhibitor increased significantly over the past decade, whereas the use of SU decreased. However, SUs still remain the most commonly prescribed second-line agents with metformin in 2013.