The Relationship between HbA1c Levels and Random Blood Glucose in Patients with Type 2 Diabetes Mellitus

Abstract

Diabetes mellitus is a chronic metabolic disease characterized by hyperglycemia resulting from impaired insulin secretion, insulin action, or both. Assessment of glycemic control is essential in the management of diabetes mellitus, and two commonly used laboratory parameters are Hemoglobin A1c (HbA1c), which reflects the average blood glucose level over the previous 2–3 months, and random blood glucose (RBG), which represents the blood glucose level at the time of examination. This study aimed to determine the relationship between HbA1c levels and RBG levels in patients with hyperglycemia. An observational analytic study with a cross-sectional design was conducted using medical record data from August 2025, including patients aged ≥18 years who had complete HbA1c and RBG examination results. Data analysis was performed using the Spearman rho correlation test. The results showed that HbA1c levels ranged from 5.75% to 14.0%, while RBG levels ranged from 50 to 357 mg/dL. The correlation analysis demonstrated a strong positive relationship between RBG and HbA1c levels, with a correlation coefficient of r = 0.87. In conclusion, there is a strong relationship between random blood glucose and HbA1c levels in patients with hyperglycemia, indicating that RBG is associated with long-term glycemic control, although HbA1c remains the primary parameter, and patient adherence to dietary management, healthy lifestyle, and regular monitoring plays an important role in achieving optimal glycemic control.