A recently-conducted study by Abrahami et al. using CPRD GOLD data assessed the association between use of a certain antidiabetic medication class (Dipeptidyl Peptidase-4 Inhibitors, DPP4i) and the risk of inflammatory bowel disease (IBD, a group of disorders of the gastrointestinal tract). The study found an increased risk of IBD in patients, who were previously diagnosed with diabetes mellitus (a disease in which the body has problems controlling blood sugar) and who were using DPP4i, compared to diabetic patients using other antidiabetic drugs.
The purpose of this study is to compare the data generated by this previous study with results generated using a different study methodology. We will thereby compare two different methods to analyse the same study question using the same database.
Since DPP4i are an important group of medications in the treatment of patients with diabetes, it is of public health importance to know whether the use of these drugs is indeed associated with an increased risk of IBD.
The objective of this study is to implement an active comparator, new user cohort design (ACNU) in CPRD GOLD data to assess the association between dipeptidyl peptidase-4 inhibitor (DPP4i) use and the risk of inflammatory bowel disease (IBD) in patients with diabetes type 2. We will compare our results with a previously conducted study on the same topic (Abrahami et al.) also using the CPRD to analyse the impact of study design differences on comparative safety results.
The study population will include patients aged ?18 years who received ?2 prescriptions for a DPP4i or an active comparator drug (sulfonylurea, SGLT2 inhibitors, or thiazolidinediones) between 01.01.2007 and 31.12.2017. The outcome IBD will be identified through READ codes.
We will use propensity scores to remove imbalances in measured potential confounders between ACNU cohorts and comparator drug initiators. We will follow patients from 180 days after the second prescription of a DPP4i or active comparator (the induction period) until change of treatment status, disenrollment, death, or occurrence of an IBD event. We consider a change of treatment status to be either a discontinuation of index drug class, or a switch to or addition of any study drug class. A person will be considered an exposed case of IBD from the date of a study drug prescription plus 180 days, including after treatment changes (the latent period) to account for diagnostic delay. We will estimate and compare
the cumulative incidence of IBD for each study cohort using weighted Kaplan-Meier methods
hazard ratios of IBD in DPP4i users with users of comparator drugs using weighted Cox proportional hazard models.
We will use more extensive READ codes for the outcome, and identical READ codes for a sensitivity analysis, than those used by Abrahami et al., to compare results from different study designs.
Primary outcome: Inflammatory Bowel Disease (IBD) in general
Secondary outcomes: Crohns disease; Ulcerative colitis
Susan Jick - Chief Investigator - BCDSP - Boston Collaborative Drug Surveillance Program
Sarah Charlier - Corresponding Applicant - University of Basel
Christoph Meier - Collaborator - University of Basel
Jeff Yang - Collaborator - University of North Carolina at Chapel Hill
John Buse - Collaborator - University of North Carolina at Chapel Hill
Robert Sandler - Collaborator - University of North Carolina at Chapel Hill
Tiansheng Wang - Collaborator - University of North Carolina at Chapel Hill
Til Stürmer - Collaborator - University of North Carolina at Chapel Hill
Christoph Meier - Collaborator - University of Basel