Continuous Glucose Monitoring in Hospitalized Patients with Diabetes Mellitus

The purpose of this study is to determine if patient's own Continuous Glucose Monitor (CGMs) worn in the non-ICU hospital setting have adequate accuracy for blood glucose monitoring when compared to point-of-care (POC) capillary glucose measurement, and to determine if alerts given by CGMs worn in the non-ICU hospital would prevent episodes of hyperglycemia and hypoglycemia.

All patients admitted to the hospital in inpatient or observation status and having a Continuous Glucose Monitor (CGMs) attached will be screened and identified by providers and nurses. An order will be placed by providers to continue patient's home CGM use in the hospital. "CGM patient agreement" describing the hospital policy for use of CGMs will be provided to the patient for signature. Patients will be encouraged to continue to wear their CGMs in the hospital unless their presence interferes with patients' medical care. CGM presence will be recorded by nursing in patient chart under LDA (lines, drains, airway) section. Patients will be approached by the research staff and will be offered enrollment in the study. A research consent will be reviewed with patients and will be provided for signature. Patients will be asked to continue to use their home CGMs in the hospital. If CGM sensor will reach the end of life, patients have the option to place a new sensor and to follow manufacturer recommendations for calibration and setting. Patients are responsible to provide their own sensors, transmitters and readers during the hospitalization period. If it is determined that the current sensor will interfere with hospital medical and surgical care (MRI testing, procedure at the site), patients will be asked to remove the CGM sensor and transmitter. Patients will have the option to replace the sensor after the procedure if they so desire.

Patients will continue to monitor their glucose level via CGM. For flash sensors, patients will be asked to scan their sensor at least every 8 and as needed. CGMs that require calibration will be calibrated by the patients using hospital glucometer readings. .

Patients alerted by their CGM about low glucose levels or fast downward or upward trending will have to notify their nursing staff. A POC blood glucose check will be done by nursing staff to confirm the alert or the trend. Treatment decisions will be made based on POC readings.

During hospitalization patients will continue to have their blood glucose checked with POC glucometers per hospital policy.

Treatment of diabetes and the associated complications, dosing of insulin, change from PO to insulin treatment and back to PO medications during hospitalization or at discharge will be done by the admitting team with help from the inpatient Endocrinology Consultation Service.

Decisions about insulin dosing or other diabetes treatments will be made based on hospital glucometer readings, and not based on CGM readings alone.

Patients will be asked to give the research team "provider access" to their cloud CGM software, or to allow the team to download their CGM data prior to discharge if their reading devices do not automatically synchronize with the cloud software.

CGM data will be compared with POC glucometer readings obtained in the hospital at approximately the same time. Different patient variables (demographics, comorbidities, labs and vitals, administered medications) will be collected from electronic health record and will be evaluated to determine if they interfere with CGM readings. The accuracy of CGM for glucose measurement in the hospital will be calculated.

Eligibility Criteria:
Inclusion Criteria:

* Patients with Type 1 or 2 Diabetes Mellitus,
* Patients 18 years of age or older,
* Patients admitted under medical or surgical services.
* Patients treated with diet alone, insulin (SQ, insulin pump) or oral hypoglycemic medications.
* Have their own Continuous Glucose Monitoring (CGM) monitor present on admission or able to be placed after admission.

Exclusion Criteria:

* Individuals under 18 years of age.
* COVID-19 infection.
* Infection of the skin at the CGM site requiring removal of the sensor.
* Patients with altered Mental Status.
* Patients unable to scan their flash CGMs at least every 8 hours.
* Inability to provide written consent.
* Hospitalized for less than 24 hours.