Long term patterns of use after initiation of oral antidiabetic drug therapy.

BACKGROUND: The benefits of intensive and continuous antihyperglycemic drug therapy have been extensively described. Data on long-term patterns and modifications of antihyperglycemic drug use are scarce however. Moreover randomized controlled studies may not reflect actual drug use in daily clinical practice.

OBJECTIVE: The aim of this study is to describe the longitudinal patterns of antidiabetic drug modifications after initiation of oral antidiabetic therapy in a large cohort of type 2 diabetes patients. The study will focus specifically on differences between patients who initiate treatment with metformin compared to patients who initiate treatment with sulfonylureas.

METHODS: An observational study of longitudinal patterns of use and modification of oral antidiabetic drug therapy in 3323 patients who started with oral antidiabetic treatment between 1999 and 2007. Drug dispensing data were extracted from pharmacy information systems.

RESULTS: This study shows that changes in international guidelines recommending metformin as first choice initial drug therapy in all patients were rapidly followed by prescribers. Patients starting diabetes treatment with metformin showed fewer modifications to treatment compared to patients initiating treatment with sulfonylureas. After correction for duration of follow-up, Cox regression analysis showed a hazard ratio of 0.84 for any modification in the metformin group compared to the sulfonylureas group.

CONCLUSIONS: This study shows that adherence to type 2 diabetes treatment guidelines for initial treatment is implemented on a large scale. Longitudinal patterns show that the majority of patients receive a small number of modifications to their drug regimen. Discontinuation rates were relatively low.