From Resistance to Trust: CGM Assists Patients with Low Treatment Compliance in Achieving Rapid Blood Glucose Targets and Reversing Metabolic Disorders

Medical History and Basic Information

Chief Complaint：

A 53-year-old male patient was admitted at 14:47 on January 2, 2025, due to "dry mouth, polydipsia and polyuria for 2 weeks, and elevated blood glucose for 1 day".

Present History:

Two weeks ago, after consuming excessive sweets, the patient developed dry mouth, polydipsia, polyuria, and significantly increased nocturia (6-7 times per night), which was not taken seriously. One day ago, after eating noodles and milk tea, he self-monitored his blood glucose at 23 mmol/L and then visited the outpatient clinic of our department. The outpatient examination (13:42 on January 2, 2025) showed a random capillary blood glucose of 17.6 mmol/L. He was admitted to the hospital with the diagnosis of "diabetes mellitus". Since the onset of the disease, the patient has been conscious with good mental status and appetite, poor sleep, normal stool, and urine as described above. No significant weight change was noted recently.

Past History:

He had "hypertension grade 3" for 6 years and "paroxysmal ventricular tachycardia and ventricular premature beats" for 1.5 years. He has been taking "Valsartan Tablets 1 tablet once daily, Lercanidipine Hydrochloride Tablets 1 tablet once daily, and Bisoprolol Fumarate 1 tablet once daily" for a long time. No special personal history, marital history, or family history.

Physical Examination:

Temperature (T): 36.1℃, Pulse (P): 90 beats/min, Respiration (R): 20 breaths/min, Blood Pressure (BP): 146/95 mmHg, Height: 168 cm, Weight: 104 kg, Body Mass Index (BMI): 36.85 kg/m², Abdominal obesity; no other abnormalities.

Auxiliary Examinations:

1. Laboratory Tests: Glycated Hemoglobin (HbA1c): 14.3%, C-Peptide: 3.38 ng/mL; Urinalysis: Ketone Bodies 2+, Glucose 4+; Blood Lipids: Total Cholesterol (CHO): 5.29 mmol/L, Triglycerides (TG): 2.68 mmol/L, Low-Density Lipoprotein Cholesterol (LDL-C): 3.79 mmol/L; Uric Acid: 653 μmol/L; Blood Gas Analysis, Liver and Kidney Function, Routine Blood Test, Urinary Albumin-Creatinine Ratio (UACR), Myocardial Enzymogram, Thyroid Function, etc. showed no obvious abnormalities.

2.Imaging and Functional Examinations: Vascular Ultrasound indicated bilateral common femoral artery atherosclerotic plaques; Abdominal Ultrasound suggested fatty liver; Bone Mineral Density showed T-score of -3.1. Electrocardiogram, Nerve Conduction Velocity, Sensory Vibration Threshold, and Ankle-Brachial Index (ABI) were normal. Oral Glucose Tolerance Test (OGTT) and C-Peptide Release Test were performed on January 9, 2025:

Preliminary Diagnosis:

1.Type 2 Diabetes Mellitus(T2DM), Diabetic Ketoacidosis; 2. Hypertension Grade 3 (very high risk); 3. Dyslipidemia; 4. Fatty Liver; 5. Bilateral Common Femoral Artery Atherosclerotic Plaques; 6. Osteoporosis; 7. Metabolic Syndrome.

Treatment Regimen Based on CGM Interpretation

Fingertip Blood Glucose Monitoring Regimen and Blood Glucose Control Status

Upon admission, the patient was positive for urinary ketone bodies. He was first given intravenous infusion of 5% glucose/0.9% sodium chloride + insulin for fluid replacement and ketone elimination. As a newly diagnosed diabetic with significantly elevated blood glucose and HbA1c levels at admission, after adequate fluid replacement, an intensive hypoglycemic regimen was immediately initiated based on diabetic diet education and appropriate exercise. Due to the patient's refusal to use an insulin pump, the "three short-acting + one long-acting" regimen (Insulin Glargine + Insulin Aspart) was adopted for hypoglycemic treatment to relieve glucose toxicity, restore partial islet function, and delay disease progression. Insulin dosage was adjusted according to daily fasting blood glucose, blood glucose before three meals, 2 hours after three meals, and bedtime blood glucose. At the beginning of intensive treatment, the patient refused Continuous Glucose Monitoring (CGM) and chose the traditional multiple daily fingertip blood glucose monitoring regimen.

Table1 .Fingertip Blood Glucose Monitoring Regimen and Blood Glucose Control Status

• Days 1-5 of hospitalization (January 2-January 6): The patient refused insulin pump and CGM monitoring. Under the treatment of "three short-acting + one long-acting" subcutaneous insulin injection combined with two oral hypoglycemic drugs, the monitored fingertip blood glucose still fluctuated between 10.7 mmol/L and 14.1 mmol/L.

Treatment Regimen and Blood Glucose Control Status During CGM Application

• Afternoon of Day 6 of hospitalization (January 7): Considering the poor efficacy of the "three short-acting + one long-acting" hypoglycemic regimen and the patient's low treatment compliance(failure to regularly monitor multiple daily fingertip blood glucose), the patient was communicated with again. It was suggested to switch to insulin pump for more flexible blood glucose regulation, and CGM was recommended to grasp the 24-hour blood glucose information and understand blood glucose fluctuation rules for timely and flexible adjustment of the hypoglycemic regimen. The patient agreed to the above plan.

Note: TIR: Time when glucose is within the target range (3.9~10.0 mmol/L); TAR: Time when glucose is above the target range (>10.0 mmol/L); TBR: Time when glucose is below the target range (<3.9 mmol/L)

• January 9: CGM indicated that the patient's TIR was still not up to standard (<70%). Considering the patient's obese body type, large food intake, and irregular meal times, it was suggested to add Dulaglutide Injection for hypoglycemia, which also has a weight loss effect. After medication, CGM showed that blood glucose gradually stabilized.

Table 3. Treatment Regimen and Blood Glucose Control Status During CGM Application

Note: TIR: Time when glucose is within the target range (3.9~10.0 mmol/L); TAR: Time when glucose is above the target range (>10.0 mmol/L); TBR: Time when glucose is below the target range (<3.9 mmol/L)

• January 10: After the patient discontinued the insulin pump and switched to the regimen of subcutaneous Insulin Aspart 30 Injection + Dulaglutide combined with oral hypoglycemic drugs, CGM showed that TIR gradually increased within the recommended target range (>70%) until it approached 100%, indicating improving blood glucose control. This regimen and lifestyle were maintained, and blood glucose control was continuously monitored.
• January 13: The patient was discharged with stable condition. After discharge, the patient continued to wear CGM until the sensor expired.

CGM Assessment Report

1. Core CGM Indicators: The report showed that the monitoring time accounted for 98.9%, with good data adequacy. The patient's blood glucose coefficient of variation (CV), TIR, and TAR all met the standards, and no hypoglycemia was found (TBR 0%). In addition, the patient's estimated glycated hemoglobin was 7%, which was significantly improved compared with 14.3% at admission. The patient's overall blood glucose control was good, and he was discharged with this lifestyle and treatment regimen.

Figure 1. Glucose Overview Chart

2. Ambulatory Glucose Profile (AGP): The median line was almost flat and within the target range, with small daytime glucose variability. The Interquartile Range (IQR) curve was smooth and well-fitted to the median line, indicating an appropriate treatment regimen. The Interdecile Range (IVR) curve fluctuated significantly, especially a noticeable fluctuation at 8:00 AM, which was confirmed to be caused by the oral glucose tolerance test after reviewing the daily blood glucose fluctuation curve.

Figure 2. AGP Chart

3. Daily Glucose Overview: Blood glucose increased significantly on January 9, which was related to the suspension of the insulin pump for OGTT. Blood glucose reached a peak 2 hours after OGTT. After the end of OGTT, the insulin pump was restarted with a temporary infusion of 6U insulin, and blood glucose gradually decreased and stabilized.

Figure 3. Daily Glucose Overview

Case Summary

This patient was a newly diagnosed diabetic with a short course of disease, abdominal obesity, and multiple comorbidities including hypertension, dyslipidemia, and atherosclerosis. From initially refusing insulin pump and CGM at admission to later using insulin pump and CGM to develop an appropriate hypoglycemic regimen for rapid blood glucose target achievement, the assistance of technology was impressive. During the entire treatment period, medication adjustments were patient-centered, considering the patient's acceptance and cooperation. Individualized treatment was continuously adjusted: from "three short-acting + one long-acting" subcutaneous insulin injection combined with oral Metformin and Acarbose, to discontinuing the "three short-acting + one long-acting" regimen and switching to insulin pump, to adding once-weekly subcutaneous Dulaglutide, and finally to discontinuing the pump and switching to twice-daily subcutaneous premixed insulin. Multiple adjustments to the hypoglycemic regimen were made until blood glucose control met the target.

Considering the patient's low treatment compliance(failure to record self-diet and regularly monitor fingertip blood glucose before three meals, 2 hours after three meals, and at bedtime as prescribed), CGM was recommended for blood glucose monitoring. Through CGM, the patient's overall blood glucose level and TIR compliance rate could be continuously observed, and an individualized hypoglycemic regimen could be timely formulated and adjusted. Moreover, after adjusting the hypoglycemic regimen, insulin dosage could be promptly adjusted based on CGM blood glucose fluctuations, leading to gradually stable blood glucose, increasing TIR, and even approaching 100%. The patient was very satisfied with this outcome.

The development of CGM technology has made Time in Range (TIR) another important indicator for blood glucose management besides HbA1c, providing a new perspective for blood glucose management in diabetic patients. The application of CGM has realized the informatization of patients' blood glucose management. Both doctors and patients can real-time observe the patients' blood glucose fluctuation rules. It not only reduces the pain of traditional fingertip blood glucose monitoring for patients, greatly improves patient compliance, reduces the incidence of hypoglycemia, shortens the hospital stay, and increases the blood glucose target achievement rate; but also helps doctors fully grasp the patients' blood glucose changes, provides reference value for clinical decision-making, improves the efficiency of medical staff, and enhances the hospital's blood glucose management level.