Health care costs associated with treatment modification in type 2 diabetes mellitus patients taking oral anti-diabetic drugs.

Objectives: To compare health care costs among patients with type 2 diabetes mellitus (T2DM) who added a new oral anti-diabetes drug (OAD) to an initial regimen with those who up-titrated their initial OAD.

Methods: Insurance claims data were obtained from 94 health plans for patients aged ≥18 years with ICD-9-CM diagnosis of T2DM during the period Jan. 1, 2001-June 30, 2007, and a newly prescribed metformin or sulfonylurea monotherapy.