The association of dipeptidyl peptidase IV inhibitors and other risk factors with bullous pemphigoid in patients with type 2 diabetes mellitus: A retrospective cohort study.

Background: Bullous pemphigoid (BP) is an autoimmune blistering skin disorder with unknown etiology. Evidence revealed that dipeptidyl peptidase IV inhibitors (DPP4i) may increase the associated risk. This study aimed to evaluate the relationship of BP with the administration of DPP4i and other risk factors in patients with type 2 diabetes mellitus (T2DM).

Methods: Using the Taiwan National Health Insurance Database (NHIRD) from 2009 to 2013, we identified patients with T2DM and the use of DPP4i 12 weeks or greater as a DPP4i cohort and patients with T2DM who never use DPP4i as a control cohort. They were frequency matched on gender and age within 5 years at a ratio of 1:2. The Cox proportional hazard regression model was used to estimate the hazard ratios (HRs) and confidence intervals (CIs) for the cohorts.

Results: A total of 14,187 individuals taking DPP4i and 28,374 matched cohorts without taking DPP4i were included. The incidence rate of BP was higher in DPP4i cohort than in control cohort (1.41 vs. 0.59 per 1000 person-years; adjusted HR 2.14, 95% CI = 1.02-4.50). The cumulative event rate of BP in DPP4i cohort was higher than in control cohort (log-rank test, p = .01). Patients with dementia and taking spironolactone had a higher associated risk to develop BP; lower associated risk in patients taking metformin.

Conclusions: In patients with T2DM, subjects taking DPP4i, having dementia, and taking spironolactone were associated with an increased risk for the development of BP.