Clinical and Demographic Correlates of Glycemic Variability in Patients with Diabetes: Insights from Longitudinal Multivariate Data

Background: Intra-individual variability in hemoglobin A1c (HbA1c) levels over time is increasingly recognized as a critical indicator of glycemic instability and a predictor of diabetes-related complications. Objective: This study aimed to identify clinical and demographic predictors of high intra-individual HbA1c variability, compared with low variability, among patients with diabetes in Oman. Methods: A retrospective observational analysis was conducted using routinely collected clinical data from patients with diabetes. Patients were classified into two groups based on the standard deviation of HbA1c: low (≤1) and high (>1). We used t -tests for continuous variables and the Chi-square test for categorical variables. Bias-reduced binary logistic regression was used to identify independent predictors of high HbA1c variability. Results: Several clinical and demographic factors were significantly associated with high HbA1c variability. Higher baseline HbA1c [odds ratios (OR) =1.111; 95% confidence interval (CI): 1.085–1.139; P < 0.001], fasting blood sugar (OR = 1.043; 95% CI: 1.030–1.055; P < 0.001), systolic blood pressure (OR = 1.003; 95% CI: 1.000–1.005; P = 0.020), and creatinine levels (OR = 1.002; 95% CI: 1.001–1.003; P < 0.001) were associated with increased odds of high variability. Conversely, lower diastolic blood pressure (OR = 0.993; 95% CI: 0.990–0.997; P < 0.001) and low-density lipoprotein cholesterol (OR = 0.884; 95% CI: 0.853–0.917; P < 0.001) were associated with reduced variability. Conclusions: High HbA1c variability is significantly associated with adverse glycemic and metabolic profiles. These findings highlight the utility of variability metrics in routine diabetes monitoring and suggest the need for targeted interventions for patients at risk of glycemic instability.