CGM-Based Assessment of Factors Linked to Abnormal Glycemic Variability in T2D

Continuous glucose monitors (CGMs), devices that attach to the body and provide real-time blood glucose levels, represent a significant advancement in diabetes care. The devices offer a more complete picture of glycemic control compared to traditional self-monitoring of blood glucose.

In a retrospective observational study, researchers investigated factors associated with glucose fluctuations in patients with type 2 diabetes (T2D) using CGMs.¹

Glucose Fluctuations in T2D

Many factors can influence high blood sugar, including food and physical activity choices; dehydration; skipping or not taking enough medication that lowers blood sugar; taking medication incorrectly; and hormone changes. Physical or emotional stress changes could also cause high blood sugar due to a release of hormones.²

Significant glucose swings in patients with T2D can reduce treatment effectiveness and cause short-term clinical issues. Over time, these fluctuations may also increase the risk of diabetic complications and cardiovascular events. Previous research has shown that sharp changes in the blood glucose trigger oxidative stress and inflammation that damage blood vessels, even when average glucose levels appear well controlled. Researchers noted that this explains why some patients with good hemoglobin A1c (HbA1c) levels still develop complications, highlighting the need to manage glycemic variability.¹

Although glycemic variability is increasingly recognized as important in diabetes care, factors driving abnormal glucose fluctuations in individuals with T2D are not understood. Identifying these contributors is essential for creating targeted strategies to improve glucose stability.¹

What Influences Glucose Swings in T2D?

In this retrospective observational study, researchers analyzed patient records and CGM data to determine which patient characteristics are linked to abnormal variability and identify subgroups at higher risk who may benefit from more tailored treatment. A total of 252 patients with T2D who underwent CGM during hospitalization.¹

After admission, patients wore a CGM device, which recorded interstitial glucose every 5 minutes, averaging to about 288 readings per day. Data from the 3 days of intensive insulin therapy were extracted for analysis to minimize treatment-related variability.¹

Participants were divided into a high-glycemic variability group and a low-variability group. Glucose fluctuation measures were calculated from 3 days of CGM during hospitalization, along with clinical and laboratory data. Statistical analyses, including t-tests, Mann-Whitney U tests, logistic regression, and restricted cubic spline models, were used to compare groups and identify factors associated with high variability.¹

Results demonstrated that the high glycemic group differed significantly from the low glycemic group in disease duration, body mass index (BMI), triglyceride levels, and C-peptide levels. Patients with high glycemic variability. Patients with high glycemic variability also had lower time in range and higher time above range and time below range.¹

Further results from multivariate analysis showed that low BMI, low C-peptide, and longer disease duration were risk factors for abnormal glucose fluctuations. Multivariable analysis showed that low BMI, low C-peptide, and longer disease duration were risk factors for abnormal glucose fluctuations.¹

“The results of the study indicated that disease duration, body mass index, triglycerides, and C-peptide may be important factors associated with glucose fluctuation,” the authors said in the study.¹

The findings suggest that CGM reveals glucose fluctuations that traditional measures like HbA1c and fasting glucose may miss. Patients with longer disease duration, lower BMI, and reduced pancreatic function are more likely to experience significant variability. The study authors noted that these higher-risk groups could benefit from closer monitoring and education to improve self-management.¹

REFERENCES

1. Zhong N, Zhang A, Chen J, Hu Z, Nie R, Huang J, Wu M, Pan H. Factors Associated with Blood Glucose Fluctuations in Patients with Type 2 Diabetes: A Retrospective Observational Study Using Continuous Glucose Monitoring. Diabetes Metab Syndr Obes. 2025 Nov 5;18:4049-4057. doi: 10.2147/DMSO.S542547

2. Mayo Clinic Staff. Blood sugar levels can fluctuate for many reasons. News release. Mayo Clinic. March 13, 2024. Accessed November 14, 2025. https://www.mayoclinic.org/diseases-conditions/diabetes/expert-answers/glucose-levels/faq-20424316