This study is a multicenter, prospective, non-interventional real-world study to evaluate the clinical outcomes of biweekly cofrogliptin versus daily linagliptin as an add-on therapy in Chinese adult T2D patients.

About 43 hospitals from different parts of China will take part in this study. Patients aged ≥18 years who have been previously treated with a stable dose of insulin and no more than three classes of oral antidiabetic drugs (OADs) for at least 12 weeks without adequate glycemic control will be enrolled and assigned to either cofrogliptin once every 2 weeks cohort or linagliptin once-daily cohort based on the prescription. Initiation of cofrogliptin or linagliptin treatment was at the treating physician's discretion.

Enrolled participants will undergo routine follow-up for up to 24 weeks. During the follow-up period, data will be collected from face-to-face participant-investigator visits at the beginning of the study (0 weeks, visit 1), early stage (4 weeks, visit 2), mid-stage (12 weeks, visit 3) and at the end of the study (24 weeks, visit 4). Data sources include patient medical records, diaries, self-monitoring of blood glucose (SMBG), and questionnaires. No additional diagnostics, monitoring procedures, or interventions outside of usual clinical practice will be applied to the participants. The project will probably last for about 24 months.

Inclusion Criteria:

1. Sign the informed consent form.
2. Aged ≥18 years.
3. Diagnosed with type 2 diabetes mellitus (meeting the 1999 WHO diagnostic criteria).
4. Recently tested HbA1c 7%-9% and FPG ≤11 mmol/L, with stable treatment using insulin ± OADs for at least 12 weeks prior to enrollment. Insulin regimens are limited to: basal insulin once daily or once weekly, premixed insulin once or twice daily, or IDegAsp once or twice daily. OAD classes are limited to metformin, SGLT2 inhibitors, and α-glucosidase inhibitors and with no more than three agents in total.
5. Willing to start or have already initiated cofrogliptin or linagliptin treatment (at the physician's discretion in accordance with clinical practice). The treatment decision is independent of study enrollment, must be made before signing the informed consent, and cofrogliptin or linagliptin initiation must occur either within 2 weeks before or within 2 weeks after signing the informed consent.

Exclusion Criteria:

1. Allergic to the study drug.
2. Diagnosed with type 1 diabetes.
3. Unable to comply with study-specific procedures.
4. Current or planned pregnant, or currently breastfeeding.
5. With any other situation judged by the investigator, that is unsuitable for participation in this trial.

Real-world adult population with type 2 diabetes in China.