A Study to Learn How Well a Monitoring System Called Continuous Glucose Monitoring (CGM) Which Measures Glucose on an Ongoing Basis Works and How Safe it is in Chinese Patients in Usual Practice

Researchers are looking for a better way to help Chinese people who have diabetes to monitor their blood sugar (blood glucose) situation.

There are 2 types of diabetes. In people with type 1 diabetes, the body's immune system attacks and destroys cells in the pancreas that produce a hormone called insulin. In people with type 2 diabetes, the body does not make enough insulin or does not use insulin well. This results in high blood glucose levels. Over time, high blood glucose levels can cause damage to certain parts of the body. These include the eyes, the kidneys, the nerves, and the heart.

There are tests and devices available for doctors and patients to measure blood glucose levels. Repeated measurements of blood glucose levels are needed to see whether the treatments that prevent blood glucose levels from becoming too high work well and to notice when the blood glucose is decreasing too much. Such tracking of the blood glucose is also called blood glucose monitoring. Blood glucose monitoring tests and devices can however be difficult to use, and one test or device may not work for all patients. Researchers think that better monitoring systems would help patients improve the control of their blood glucose levels. This could help stop their diabetes from getting worse.

In this study, the researchers want to learn more about how well a new monitoring system called CGM works in Chinese patients with diabetes. CGM is a continuous glucose monitoring system. It regularly measures the level of glucose in the tissue throughout the day and night. CGM is made up of a small sensor that patients apply in the belly region where it is placed just under the skin, into the so-called subcutaneous tissue. The sensor measures the level of glucose in the fluid that surrounds cells in the subcutaneous tissue. It also has a transmitter which attaches to the sensor and sends via Bluetooth the results to a device, which can instantly display the glucose level. The glucose levels can then be used to adjust the treatment.

The main purpose of this study is to learn how well CGM monitors glucose levels in Chinese patients when used in usual practice. To answer this question, the researchers will compare the glucose levels collected with the CGM monitor to the blood glucose levels collected with another type of monitoring called "venous blood glucose testing". This is where a blood sample is taken from the veins, and then the level of glucose in the blood sample is measured.

The study will include adult Chinese patients who have type 1 or type 2 diabetes and who the study doctors think need to monitor their diabetes using CGM and venous blood glucose testing.

There will be no treatments given as part of this study. The device will be worn up to a maximum of 14 days. The patients will get training on how to use the CGM monitor and will attach it to their belly on Day 1 of the study.

The researchers will then collect the information about their glucose levels. The study doctors will also take blood samples and measure blood glucose levels using venous blood glucose testing. They will compare the glucose levels recorded from the blood samples to the glucose levels recorded by CGM at the closest time points. After wearing CGM for 14 days, the study doctors will remove it from the patients' bellies. About 3 days later, the researchers will call the patients to check if they have any swelling or areas of rash where CGM was worn. The patients may also take photos of the area and send these to the study doctors.

During the study, the study staff will:

* take blood samples as part of the usual care
* compare glucose levels recorded by CGM to the levels recorded from the venous blood glucose tests
* check the skin for any swelling or areas of rash where CGM was worn
* record any instances of CGM errors or alarms for when glucose levels are too high or too low
* check the patients' overall health
* ask the patients about how they are feeling and what medical problems they are having.


Eligibility Criteria:
Inclusion Criteria:

* Adult female or male (18 years of age or older)
* Diagnosed with type 1 or type 2 diabetes mellitus
* Decision to initiate venous blood glucose testing and CGM as per investigator's routine treatment practice;
* Signed informed consent

Exclusion Criteria:

* Patients with moderate or more serious anemia defined as hemoglobin \< 90g/L
* Patients with moderate or more serious subcutaneous edema: grading can be referred to: mild edema (a visible mild depression of eyelid, soft tissues below the orbit, subcutaneous tissue of the anterior tibia or subcutaneous tissue of the ankle after finger pressure); moderate (all the sparse tissues of the whole body have visible edema with obvious or deeper tissue depressions after finger pressure and slow subsidence); severe (severe edema of tissues all over the body, the skin of the low hanging part of the body is tense and shiny, and there may even be fluid exudation, sometimes accompanied by fluid accumulation in the thoracic cavity, abdominal cavity and sphincter cavity)
* Pregnant women