HbA1c Variability and Its Association with Complications Among Patients with Type 2 Diabetes in Changklang District, Nakhon Si Thammarat

Abstract

This study aimed to identify factors associated with HbA1c variability and to assess the relationship between HbA1c variability and diabetes-related complications among individuals with type 2 diabetes mellitus (T2DM) receiving care in Chang Klang District, Nakhon Si Thammarat Province. A total of 300 individuals with T2DM were included. Participants were selected using criterion-based sampling from the hospital’s electronic medical record system, which provided routinely collected secondary clinical data. Independent variables included sociodemographic characteristics (e.g., age, sex, body mass index) and health-related factors (e.g., comorbidities, medication use, and laboratory parameters). The primary dependent variable was HbA1c variability. Descriptive statistics (frequency, percentage, mean, and standard deviation) were used to summarize participant characteristics. Inferential analyses included chi-square tests, independent t-tests, Pearson’s correlation, and multivariate logistic regression. The analysis demonstrated that several personal and clinical factors—specifically BMI≥23 kg/m², a history of hypoglycemia or hyperglycemic crisis, metformin use, fasting blood sugar (FBS), and LDL cholesterol levels—were significantly associated with HbA1c variability (p<0.05). Individuals with BMI≥23 kg/m² had 1.63 times increased odds of high HbA1c variability (adjusted OR=1.63; 95% CI=1.03-3.66; p=.046). A history of hypoglycemia or hyperglycemic crisis was likewise associated with 2.53 times higher odds of HbA1c variability (adjusted OR=2.53; 95% CI=1.10-5.83; p=.029). In contrast, metformin use was protective, reducing the odds of high HbA1c variability by 0.62 times or approximately 38% (adjusted OR=0.62; 95% CI=0.50-0.81; p=.025). Higher FBS levels were also associated with increased odds of HbA1c variability (adjusted OR=1.12; 95% CI, 1.06-1.23; p=.005), as were elevated LDL cholesterol levels (adjusted OR=2.09; 95% CI, 1.03-4.23; p=.042). Meanwhile, age, sex, duration of diabetes, cardiovascular disease, and triglyceride levels were not significantly associated with HbA1c variability. HbA1c variability was positively correlated with a history of hypoglycemia or hyperglycemic crisis (r=0.450; p=.021), suggesting that greater variability is associated with an increased likelihood of acute glycemic events with statistical significance at .05.