Dipeptidyl peptidase-4 inhibitors reduce the incidence of first cardiovascular events in Japanese diabetic patients

Background Dipeptidyl Peptidase-4 (DPP-4) inhibitors do not suppress cardiovascular events in diabetic patients with a history of cardiovascular disease. However, the effect of DPP-4 inhibitors on cardiovascular events in Japanese diabetic patients is unclear. Therefore, we investigated whether DPP-4 inhibitors alter the incidence of cardiovascular events in Japanese diabetic patients without a history of cardiovascular events. Methods The Japanese Primary Prevention of Atherosclerosis with Aspirin for Diabetes (JPAD) trial was a multicenter, prospective, randomized, open label, blinded, end-point study conducted from 2002 to 2008. After completion of the JPAD trial, we followed up the patients until 2019. Patients who had had a cardiovascular event by the 2013 follow-up were excluded from the study. JPAD patients were divided into a DPP-4 group and a non-DPP-4 group based on whether they were taking DPP-4 inhibitors at the 2013 follow-up because few patients took DPP-4 inhibitors before 2013. We investigated the incidence of cardiovascular events consisting of coronary events, cerebrovascular events, heart failure requiring hospitalization, and aortic and peripheral vascular disease in 1099 JPAD patients until 2019. Results During the observation period from 2013 to 2019, 37 (7%) first cardiovascular events occurred in the DPP-4 group (n = 518) and 66 (11%) in the non-DPP-4 group (n = 581). The incidence of cardiovascular events was significantly lower in the DPP-4 group than in the non-DPP-4 group (Log-Rank P = 0.0065). Cox proportional hazards model analysis revealed that the use of DPP-4 inhibitors (hazard ratio 0.65; 95% confidence interval 0.43–0.98; P = 0.038) was an independent factor after adjustment for age ≥ 65 years, hypertension, statin usage, and insulin usage. Conclusions Our findings have demonstrated that the use of DPP-4 inhibitors may be associated with a reduced incidence of first cardiovascular events in Japanese diabetic patients. The results require confirmation in randomized controlled trials.