This is a cross-sectional observational study aiming to examine and compare the impact of incretin based therapies i.e. dipeptidyl peptidase-4 (DPP4) inhibitors and glucagon-like peptide-1 (GLP-1) analogues, on endothelial progenitor cells (EPCs) and its mobilising factor, stromal derived factor-1 α (SDF-1 α), in patients with type 2 diabetes mellitus (T2DM) who are well established on those treatments. EPCs provide vascular protection by means of endothelial repair and neogenesis. This endothelial protective effect may potentially benefit patients affected by micro or macrovascular complications arising from vascular injury e.g. cardiovascular disease in T2DM. The study is of particular interest as a small study has shown an increase in level of circulating EPC in patients treated with DPP-4 inhibitors, thought to be mediated via the up regulation of its mobilising factor SDF-1 α.