Association of dipeptidyl peptidase 4 inhibitors with risk of metastases in patients with type 2 diabetes and breast, prostate or digestive system cancer

Aims: Experimental and animal studies have supported the hypothesis that dipeptidyl peptidase-4 inhibitors (DPP-4i) may accelerate tumor metastasis. The aim was to analyze the relationships between DPP-4i therapy with risk of metastases in type 2 diabetes patients with breast, prostate and digestive organ cancers. Methods: Type 2 diabetes patients with first diagnoses of breast, prostate or digestive organ cancer were selected in general and internal medicine practices (Disease Analyzer Germany: 01/2008-12/2014). Propensity score matching between DPP-4i users and non-users was carried out for age, sex, diabetes duration, and metformin use. Time-dependent Cox regression models were used to estimate hazard ratios (HR) for metastases further adjusting for HbAlc, body mass index, comorbidity and co-therapy with glucose-lowering drugs (3-4 years follow-up). Results: 668 patients with newly diagnosed breast cancer, 906 with prostate cancer and 908 with digestive organ cancer were analyzed. In Cox regression, use of DPP-4i was not associated with an increased risk of metastases in patients with breast (adjusted HR, 95%Cl: 1.00, 0.49-2.02), prostate (0.98, 0.54-1.77) or digestive organ cancers (0.97, 0.57-1.66). Conclusions: This first observational study in patients with type 2 diabetes and breast, prostate or digestive organ cancer found no increased risk of metastases in DPP-4i users. (C) 2017 Elsevier Inc. All rights reserved.