CGM Real-Time Feedback Guides Elderly Diabetes Treatment: From "Hyperglycemic Crisis" to "Stable Target Achievement"

Medical History and Basic Information

Chief Complaint：

A 65-year-old female patient visited the Department of Ophthalmology of our hospital for "cataract surgery".

Present History：

More than one year ago, the patient developed dry mouth, polydipsia, polyphagia, and hyperphagia without obvious cause. Her daily water intake reached 3000 mL, accompanied by polyuria (urine output equivalent to water intake), weight loss of 4 kg, and increased nocturia (3 times/day). No obvious foamy urine was noted, and the symptoms were not taken seriously. Currently, the patient visited the Department of Ophthalmology of our hospital for cataract surgery, where elevated blood glucose was detected (fasting blood glucose: 14.5 mmol/L). For further treatment, she was referred to the outpatient clinic of our department. Random blood glucose (GLU): 14.10 mmol/L, glycated hemoglobin (HbA1c): 15.1%. The diagnosis of diabetes mellitus was considered, and she was admitted to our department.

Physical Examination：

Blood Pressure (BP): 120/74 mmHg; Body Mass Index (BMI): 21 kg/m².

Auxiliary Examinations：

Lipid Profile: Total Cholesterol (TC): 6.29 mmol/L ↑, Low-Density Lipoprotein Cholesterol (LDL-C): 3.80 mmol/L ↑;

Glycated Hemoglobin Determination: HbA1c 15.1% ↑;

Blood Glucose and C-Peptide:

Random Urine Protein/Creatinine Ratio (5-item panel): U-alb/CR 86.94 mg/g ↑;

Insulin Antibody Panel: Negative;Chest X-ray: 1. No obvious abnormalities in bilateral lung X-ray examination; 2. Aortic sclerosis; 3. Possible old fractures of the 5th and 6th right anterior ribs;Electrocardiogram (ECG): Normal;Vascular Color Doppler Ultrasound (Carotid, Vertebral, Subclavian, Innominate Arteries): Bilateral carotid intima-media uneven thickening with multiple plaques; diffuse stenosis of the right vertebral artery (physiological); right subclavian artery plaque.

Diagnosis:

1.Type 2 Diabetes Mellitus(T2DM) ; 2. Diabetic Macrovascular Disease (multiple carotid plaques); 3. Diabetic Nephropathy (G2A2 stage); 4. Cataract; 5. Dyslipidemia.

Treatment Plan Guided by Continuous Glucose Monitoring (CGM) Interpretation

The patient was a newly diagnosed elderly diabetic with significantly elevated blood glucose, no ketoacidosis, but complicated with chronic diabetic complications including diabetic nephropathy and diabetic macrovascular disease, and poor islet function. Blood glucose needed to be controlled as soon as possible before cataract surgery.

The "hypoglycemic & lipid-lowering & urine protein reduction" treatment plan was adopted for this case:

• - Hypoglycemic therapy: Intensive treatment with insulin pump;
• - Lipid-lowering therapy: Atorvastatin 10 mg qn;
• - Urine protein reduction: Irbesartan 150 mg qd.

Adjustment strategies (drug adjustment, dietary intervention, exercise recommendations) were made based on the daily blood glucose change curves and/or Ambulatory Glucose Profile (AGP) from CGM.

Daily Blood Glucose Change Curves from CGM

The "dual C therapy" combining CGM and insulin pump [CGM & Continuous Subcutaneous Insulin Infusion (CSII)] is currently the optimal regimen for intensive insulin therapy in diabetic patients. CGM indicated that the patient had postprandial hyperglycemia, and fasting blood glucose returned to normal on the second day. Therefore, the basal insulin rate was maintained unchanged, and the preprandial bolus dose was increased.

• Day 4: The patient's blood glucose was stable with an average of 8.4 mmol/L, TIR reaching 86.5%, and blood glucose coefficient of variation (CV%) of 18.8%. Considering the patient was elderly with macrovascular disease, CV% needed to be controlled below 36% to reduce the risk of complications.
• Day 5: Blood glucose trend remained stable; switched to Insulin Aspart 30 (28U and 20U, injected 1 hour before breakfast and dinner respectively).
• Day 6: CGM indicated a small peak of post-breakfast blood glucose, elevated post-lunch blood glucose, and low pre-lunch blood glucose. Acarbose was added to "flatten peaks and fill valleys", improving postprandial hyperglycemia and preprandial hypoglycemia.

Through 4 days of intensive insulin therapy, the patient's blood glucose quickly reached the target with TIR of 86.5%, stable blood glucose, and no hypoglycemia. Subsequently, the regimen was switched to twice-daily premixed insulin + Acarbose, with an average blood glucose of 6.9 mmol/L and TIR of 91%, which was highly satisfactory to both doctors and the patient.

Case Summary

This patient was a newly diagnosed elderly diabetic with significantly elevated blood glucose at admission, complicated with diabetic nephropathy (G2A2) and macrovascular disease (carotid plaques), indicating poor daily blood glucose management. By wearing CGM, we were able to comprehensively and dynamically monitor the patient's blood glucose changes, which not only provided a precise basis for adjusting insulin pump doses but also helped identify blood glucose fluctuations that are difficult to detect with traditional fingertip blood glucose monitoring.

CGM data showed that the patient mainly had postprandial hyperglycemia. Based on the blood glucose trend, we guided the patient to optimize the dietary structure, appropriately reduce carbohydrate intake, and increase high-quality protein intake to prevent the further progression of diabetic nephropathy and muscle loss. Meanwhile, recommendations for moderate postprandial exercise and reasonable adjustment of preprandial bolus insulin dose were given, leading to rapid and high-quality achievement of blood glucose targets.

In addition, CGM effectively monitored nocturnal blood glucose changes, ruled out the risk of nocturnal hypoglycemia, and made the treatment process safer and more controllable. It is recommended that the patient continue to use CGM after discharge to strengthen blood glucose monitoring and improve self-management ability, thereby delaying the progression of complications and achieving long-term, stable, and individualized blood glucose control goals.