Comparisons of the risks of new-onset prostate cancer in type 2 diabetes mellitus between SGLT2I and DPP4I users: A population-based cohort study

Background: Sodium-glucose cotransporter 2 inhibitors (SGLT2I) have been suggested to reduce new-onset cancer amongst type-2 diabetes mellitus (T2DM) patients. This study aims to compare the risks of prostate cancer between SGLT2I and dipeptidyl peptidase-4 inhibitors (DPP4I) amongst T2DM patients. Design, setting and participants: This was a retrospective population-based cohort study of prospectively recorded data on male patients with T2DM who were prescribed either SGLT2I or DPP4I between 1^st January 2015 and 31^st December 2020 from Hong Kong. Methods: The primary outcome was new-onset prostate cancer. The secondary outcomes included cancer-related mortality and all-cause mortality. Propensity score matching (1:1 ratio) using the nearest neighbor search was performed and multivariable Cox regression was applied. A three-arm analysis including the glucagon-like peptide-1 receptor agonist (GLP1a) cohort was conducted. Results: This study included 42129 male T2DM patients (median age: 61.0 years old [SD: 12.2]; SGLT2I: n = 17,120; DPP4I: n = 25,009). In the propensity score matched cohort, the number of prostate cancers was significantly lower in SGLT2I users (n = 60) than in DPP4I (n = 102). Over a follow-up duration of 5.61 years, SGLT2I was associated with lower prostate cancer risks (HR: 0.45; 95% CI: 0.30-0.70) than DPP4I after adjustments. The subgroup analyses showed that the interactions between SGLT2I and age, hypertension, heart failure, and GLP-1a were not statistically significant. The result remained consistent in the sensitivity analysis. Conclusion: The study demonstrated SGLT2I was associated with lower risks of new-onset prostate cancer after propensity score matching and adjustments compared to DPP4I amongst T2DM patients.