Factors Associated with Blood Glucose Fluctuations in Patients with Type 2 Diabetes: A Retrospective Observational Study Using Continuous Glucose Monitoring.

Objective: To investigate the factors associated with glucose fluctuations in patients with type 2 diabetes mellitus (T2DM) using continuous glucose monitoring (CGM). Methods: This retrospective observational study included 252 patients with T2DM who underwent CGM during hospitalization. Participants were stratified into two groups based on their coefficient of variation (CV) of glucose: the high-CV group (CV ≥ 33%, n=53) and the low-CV group (CV < 33%, n=199). Glucose fluctuation indices were calculated from CGM data. All patients underwent 3-day CGM during hospitalization. General clinical data and biochemical indicators were collected. Statistical analyses included t-tests, Mann-Whitney U-tests, logistic regression, and restricted cubic spline models. Results: Significant differences were observed between the two groups in terms of disease duration, BMI, triglycerides, and C-peptide levels (P<0.05). Compared to the low-CV group, patients in the high-CV group had significantly lower Time in Range (TIR) and higher Time Above Range (TAR) and Time Below Range (TBR) (all P<0.001).Multivariate Logistic regression analysis revealed that low BMI, low C-peptide, and longer disease duration may be risk factors for abnormal blood glucose fluctuations in T2DM patients (P<0.05). Linear regression revealed a significant negative correlation between C-peptide levels and CV (β = -0.02, P=0.003).A threshold effect was observed between C-peptide and the coefficient of variation(CV) of blood glucose (Cut-off=0.913 nmol/L), with CV increasing by 0.07 per 1 nmol/L decrease in C-peptide below this threshold (P=0.029). Conclusion: This study suggests that patients with longer disease duration, lower BMI, and poorer pancreatic function have higher odds of significant glucose fluctuations. Enhanced monitoring of glucose fluctuations and education on potential risks are recommended for these subgroups to improve self-management abilities.