The goal of this clinical trial is to learn if continuous glucose monitoring system works to improve glucose control in non-insulin-treated older adults with type 2 diabetes. The main questions it aims to answer are:

• Dose the use of continuous glucose monitoring system improve glucose control in older adults with type 2 diabetes treated with oral antidiabetic drugs only?
• Dose the use of continuous glucose monitoring system affect psychological outcomes in older adults with type 2 diabetes treated with oral antidiabetic drugs only? Researchers will compare continuous glucose monitoring to standard blood glucose monitoring to see if continuous glucose monitoring works better in glucose management.

Participants will:

• Wear continuous glucose monitoring every 2 months or standard blood glucose monitoring for 6 months
• Visit the clinic once every 2 months for follow-up
• Keep a diary of their blood glucose when continuous glucose monitoring was not used

Inclusion Criteria:

• Age ≥ 60 years at the time of screening;
• Diagnosed with type 2 diabetes mellitus;
• Treated with two or more oral antidiabetic drugs with a stable medication regimen (medication classes) during the 3 months prior to entry;
• Suboptimal glycemic control, defined as HbA1c ≥ 7.5% and ≤ 10% at screening or within 30 days prior to screening visit;
• Has a smart phone compatible with CGM and BGM systems;
• Willing and able to provide written informed consent;
• At least 240 hours (10 out of 14 days) of sensor glucose data from the blinded CGM pre-randomization phase.

Exclusion Criteria:

• Use of insulin or Glucagon-Like Peptide-1 （GLP-1） receptor agonists within 3 months prior to screening;
• Use of any CGM device within 3 months prior to screening;
• Participants were unable to tolerate tape adhesive around sensor placement area, or with medically documented allergy towards the adhesive (glue) of plasters, or with serious skin diseases (e.g. psoriasis vulgaris, bacterial skin diseases) around sensor placement area;
• Considered unsuitable for participation by the investigators, including but not limited to individuals with dementia, psychiatric disorders, extreme visual or hearing impairment that would impair ability to use real-time CGM assessed;
• Planned surgery or other procedures within the next 6 months that may interfere with scheduled follow-up visits;
• Current or anticipated acute uses of glucocorticoids (oral, injectable, or IV), that will affect glycemic control;
• Estimated glomerular filtration rate (eGFR) < 30 ml/min/1.73m2;
• Participation in any other clinical trial within 3 month prior to screening, or concurrently enrolled, or planning to participate in another trial during the study period.