AIM: We performed a retrospective cohort study, investigating the clinical outcomes including mortality and cardiovascular disease of sitagliptin compared with metformin monotherapies.

METHODS: All patients receiving monotherapy with the dipeptidyl peptidase-IV inhibitors (DPP-IV) inhibitor sitagliptin between 1 January 2007 and 31 December 2011 were identified. All-cause mortality and a composite endpoint of stroke, acute myocardial infarction (AMI) and all-cause mortality associated with sitagliptin monotherapy were compared with metformin monotherapy. In addition, as an indicator of efficacy we analysed the hazard ratio of changing treatment.

RESULTS: A total of 84 756 patients were included in the analysis, 1228 (1.4%) received sitagliptin monotherapy whereas the remaining 83 528 (98.6%) patients received metformin monotherapy. Patients using metformin were younger than patients using sitagliptin (59.0 ± 15.2 vs. 62.5 ± 13.1) were less often male (51.6 vs. 54.2%) and had longer treatment duration with monotherapy (1.8 ± 1.3 vs. 0.9 ± 1.1 years). Compared with patients receiving metformin, patients using sitagliptin showed no statistically significant excess risks of all-cause mortality [hazard ratio, 1.25; 95% confidence interval (CI), 0.92-1.71; p = 0.153] or the composite endpoint (hazard ratio, 1.22; 95% CI, 0.92-1.61; p = 0.164). However, the use of sitagliptin monotherapy was associated with an increased likelihood of changing treatment (hazard ratio, 4.88; 95% CI, 4.46-5.35; p < 0.001).

CONCLUSION: In a retrospective analysis, sitagliptin monotherapy compared with metformin monotherapy was not associated with any statistical significant increased risk of all-cause mortality or the composite endpoint, but was associated with an increased likelihood of changing glucose-lowering treatment.