CGM Assists in the Management of Drug-Induced Hypoglycemia: Precise Intervention from "Confusion" to "Glycemic Homeostasis"

Medical History and Basic Information

Chief Complaint:

A 71-year-old female patient was admitted due to "diagnosed with diabetes for 3 years and altered mental status for 4 hours."

Present History:

Three years ago, the patient was diagnosed with diabetes after elevated blood glucose was found on physical examination. She self-administered oral hypoglycemic agents (metformin and glibenclamide) without regular glucose monitoring or strict diet control. Four hours ago, her family found her confused, with slurred speech and limb movement disorders. Emergency finger-stick glucose was 1.8 mmol/L; 30 g intravenous glucose was given with symptom improvement. Cranial CT showed no acute lesions. She was transferred to endocrinology department for further treatment. Finger-stick glucose on admission was 5.4 mmol/L.

Physical Examination:

T 36.3℃, P 88 beats/min, R 22 breaths/min, BP 115/82 mmHg. Conscious, cooperative, clear speech. No jaundice, superficial lymphadenopathy, or jugular vein distension. Thyroid not enlarged. Lungs clear, no rales or wheezes. Heart rate 88 beats/min, regular, no murmurs. Abdomen soft, non-tender, no hepatosplenomegaly. Lower extremities without edema.

Auxiliary Examinations:

Routine Laboratory Test Report: Neutrophil count 7.26x10⁹/L ↑, Neutrophil percentage 76.50% ↑, Lymphocyte percentage 18.70% ↓, Plateletcrit 0.38% ↑, Large platelet count 112.00x10⁹/L ↑; July 24, 2024, Biochemical Test Report: Albumin-globulin ratio 1.13 ↓, Cystatin C 1.210 mg/L ↑, β2-microglobulin 3.63 mg/L ↑, Low-density lipoprotein cholesterol 3.53 mmol/L ↑, Homocysteine 28.40 nmol/L ↑, Magnesium 0.60 mmol/L ↓, Glucose 3.74 mmol/L ↓, Glomerular filtration rate 58.40 ml/min ↓; Biochemical Test Report: Glycated hemoglobin 6.5% ↑.

Admission Diagnosis:

1. Drug-induced hypoglycemia; 2. Type 2 diabetes mellitus (T2DM); 3. Hypertension grade 2 (very high risk); 4. Coronary atherosclerotic heart disease.

Treatment Regimen Based on Continuous Glucose Monitoring (CGM) Interpretation

During the diagnosis and treatment by endocrinologists, the patient was given treatment to correct hypoglycemia, relieve neuroglycopenic symptoms, and address various potential causes of hypoglycemia. The patient had drug-induced hypoglycemia. After discontinuing hypoglycemic drugs, recurrent hypoglycemia might occur due to the long half-life of the used hypoglycemic drugs. Therefore, continuous intravenous infusion of glucose was administered, combined with CGM to monitor blood glucose. The infusion rate of glucose was adjusted in a timely manner to avoid recurrent hypoglycemia and excessive correction of blood glucose. After the patient's blood glucose stabilized, the hypoglycemic regimen was switched to SGLT2i (ertugliflozin) combined with metformin to regulate blood glucose. Continuous blood glucose monitoring with CGM was maintained, along with diabetic diet, active treatment of comorbidities, and health education.

During the treatment, hypoglycemia was corrected quickly. Through real-time blood glucose monitoring with CGM, the glucose infusion rate was adjusted at any time according to blood glucose conditions to avoid recurrent hypoglycemia. Hypoglycemic drugs were gradually added to control blood glucose. Based on the blood glucose data feedback from CGM, the efficacy and safety of oral drugs were guided.

Note: TIR: Time in target blood glucose range (3.9~10.0 mmol/L); TAR: Time above target blood glucose range (>10.0 mmol/L); TBR: Time below target blood glucose range (<3.9 mmol/L)

• Days 1-2: CGM was used for continuous blood glucose monitoring to prevent recurrent hypoglycemia.
• Days 3-4: On days 1-2 after admission, TAR was as high as 89.5% and 68.4%, while TIR was only 10.5% and 31.6%, indicating severe blood glucose fluctuations. Metformin combined with ertugliflozin was added in a timely manner to regulate blood glucose, and CGM monitoring was continued. The patient had a blood glucose level of 3.9 mmol/L after lunch without obvious hypoglycemic symptoms, which was considered related to the addition of hypoglycemic drugs and residual metabolism of sulfonylurea drugs in the body. However, there was no severe hypoglycemia. Dietary and drug adjustments were made promptly, and no recurrent hypoglycemia occurred. The efficacy and safety of oral drugs were effectively evaluated.
• Day 5 (Discharge Day): The patient's blood glucose tended to be stable with TIR of 100% and average blood glucose of 6.7 mmol/L, without hypoglycemia. Discharge was permitted, and regular reexaminations of liver and kidney function, blood glucose, and electrolytes were advised.

Case Summary

In recent years, the American Diabetes Association (ADA), European Association for the Study of Diabetes (EASD), International Diabetes Federation (IDF), and other organizations have included CGM as an important tool for hypoglycemia management. Domestically, documents such as the "Clinical Application Guidelines for Continuous Glucose Monitoring in China" ^[1] issued by the Chinese Diabetes Society (CDS) explicitly recommend CGM for high-risk groups of hypoglycemia.

The hypoglycemia alarm function of CGM can reduce the risk of severe hypoglycemia, especially in high-risk populations [such as patients with type 1 diabetes mellitus(T1DM), T2DM on intensive insulin therapy, and patients with impaired awareness of hypoglycemia (IAH)].

Hypoglycemia is one of the core challenges in blood glucose control for diabetic patients, particularly in the elderly and those with comorbid cardiorenal diseases. Studies from the 2023 Advanced Technologies & Treatments for Diabetes (ATTD 2023) Conference further confirmed that CGM has unique advantages in identifying asymptomatic hypoglycemia and quantifying hypoglycemia risk ^[2]. Taking this case as an example, after the patient was admitted due to drug-induced hypoglycemia, real-time monitoring of blood glucose trends and data review through CGM significantly improved her blood glucose, with no recurrent hypoglycemia throughout the treatment. It is evident that CGM provides an integrated "monitoring-warning-intervention" management model for high-risk populations such as the elderly and those with comorbid cardiorenal diseases.

References:

[1] Chinese Diabetes Society. Clinical Application Guidelines for Continuous Glucose Monitoring in China (2017 Edition). Chinese Journal of Diabetes Mellitus, 2017, 09(11):667-675. DOI:10.3760/cma.j.issn.1674-5809.2017.11.002

[2] The Official Journal of ATTD Advanced Technologies & Treatments for Diabetes Conference 22‐25 February 2023 Berlin & Online