Association of morning fasting blood glucose variability with insulin antibodies and clinical factors in type 1 diabetes

The fasting blood glucose concentration in type 1 diabetes may vary without being much affected by diet and exercise. This study aimed to identify association of morning fasting blood glucose concentration variability with insulin antibodies and clinical factors. The subjects in this study were 54 patients with type 1 diabetes who had high variation of fasting blood glucose. The insulin antibody level was measured, and correlations of glycemic variability with antibody levels, binding rates, and other clinical factors were investigated. The standard deviation (SD) of the 30-day morning self-monitored fasting blood glucose concentration (FBG SD) was evaluated as an index of glycemic variability. The mean glucose level was 159.8±42.1 mg/dL and the FBG SD was 47.5±22.0 mg/dL. Glycemic variability (FBG SD) was positively correlated with insulin antibody level, but not with insulin antibody binding rate, and had a negative correlation with C-peptide immunoreactivity/plasma glucose (CPR/PG) and positive correlations with diabetes duration, basal insulin dose and bolus insulin dose. Glycemic variability was not correlated with BMI, HbA1c or age. In multiple regression analysis of glycemic variability, CPR/PG was the only significant related factor. The results showed that glycemic variability was mainly influenced by endogenous insulin secretion capacity and was high in patients with high insulin antibody levels. In some patients with a high insulin antibody titer, the antibody may have an effect on the variability of the fasting glucose concentration in type 1 diabetes.