Details
Observational studies assessing drug safety are usually conducted among incident new users of medications. However, recent studies have considered using cohorts of prevalent new users to evaluate the safety of antidiabetic drugs such as sodium-glucose co-transporter-2 inhibitors (SGLT2i) to increase sample size and expand the evaluation of the safety of antidiabetic drugs to all users. The U.S. Food and Drug Administration (FDA) initiated this study in the Sentinel System to characterize factors related to the assignment of antidiabetic treatments among patients with type 2 diabetes mellitus with and without a history of non-metformin antidiabetic medication use to understand the impact of using prevalent new users in safety evaluations of SGLT2i.
Results found that factors related to the choice of SGLT2i over dipeptidyl peptidase-4 inhibitors (DPP-4i) differ substantially among naïve, incident, and prevalent new users. SGLT2i initiators were more likely than the DPP4i users to have baseline non-metformin antidiabetic medication use in both the prevalent new users and incident new users except for sulfonylureas. Observational studies that include prevalent new users require proper design and analytic approaches to address imbalances among these populations in order to avoid bias. This study highlights that methodology to properly account for the possible imbalances within the study population should be carefully considered when studies that assess the safety of SGLT2i include prevalent antidiabetic medication new users to increase the study sample size. This study supported the FDA in interpreting studies on the safety of SGLT2i which included prevalent new users.