Real-world Study Comparing the Adherence and Effectiveness of Linagliptin vs. Acarbose

Inclusion Criteria: * Patient should fully know and understand the content of consent form, and the patient is willing and able to sign an informed consent form * Chinese outpatients with confirmed T2DM * Patients of ≥ 18, \< 80 years old * Patients currently use metformin monotherapy ≥ 1500 mg/day or maximum tolerable dose and whose glucose levels are not adequately controlled * HbA1c ≥ 7% and \< 12% * New user\* linagliptin or acarbose as combination therapy with metformin ≥ 1500 mg/day or maximum tolerable dose \*New user defined as a T2DM patient initiating linagliptin or acarbose as an add-on therapy. These are patients who are on metformin and whose glucose levels are not adequately controlled. Exclusion Criteria: * Type 2 diabetes mellitus patients who previously used any DPP-4 inhibitor/ GLP-1 receptor agonist at index date or any AGI at index date, are not eligible to participate. Also excluded are patients who currently using any glucose-lowering agent as monotherapy other than metformin. * Patients with clinically significant acute major organ or systemic disease or other condition judged by the investigator that would create difficulty for the 24-week follow-up. * Patients who participated in a clinical trial within 2 months prior to study enrolment date. * Patients diagnosed with Type 1 diabetes mellitus, secondary diabetes or gestational diabetes. * Current treatment with systemic steroids at time of informed consent or within 6 weeks prior to informed consent. * Patients with known significant GI disease as judged by the study physician.