Ambulatory treatment of type 2 diabetes in the U.S., 1997-2012

OBJECTIVE: Type 2 diabetes is increasingly common and associated with substantial morbidity and mortality. This study examines trends in the patterns and costs of drug treatment of type 2 diabetes from 1997 to 2012. RESEARCH DESIGN AND METHODS: We conducted descriptive analyses of cross-sectional data using the IMS Health National Disease and Therapeutic Index, a nationally representative audit of ambulatory physician practices in the U.S. We focused on visits for diabetes among patients 35 years of age or older. We used the IMS Health National Prescription Audit of pharmacy dispensing to derive information about drug expenditures. RESULTS: Ambulatory diabetes visits increased from 23 million treatment visits in 1997 (95% CI 21-25) to 35 million (32-37) in 2007 and declined to 31 million visits by 2012 (27-31). Between 1997 and 2012 biguanide use increased, from 23% (20-26) to 53% (50-56) of treatment visits. Glitazone use grew from 6% (4-8) in 1997 (41% [39-43] of all visits in 2005), but declined to 16% (14-18) by 2012. Since 2005, dipeptidyl peptidase-4 (DPP-4) inhibitor use increased steadily, representing 21% (18-23) of treatment visits by 2012. Glucagon-like peptide 1 (GLP-1) agonists accounted for 4% of treatment visits in 2012. Visits where two or more drug compounds were used increased nearly 40% from 1997 to 2012. Between 2008 and 2012, drug expenditures increased 61%, driven primarily by use of insulin glargine and DPP-4 inhibitors. CONCLUSIONS: Declining sulfonylurea and glitazone use has been offset by increases in DPP-4 inhibitor use and, to a lesser degree, use of GLP-1 agonists. Treatment of diabetes has grown in complexity while older treatments continue to be replaced or supplemented by newer therapies.