Endocrine Abstracts

Introduction: Glycemic variability (GV) is a major consideration when evaluating quality of glycemic control. Coefficient of glycemic variation (%CV) is the metric of choice to define GV. International consensus on continuous glucose monitoring (CGM) recommends a %CV <36. Additional studies suggest that low %CV minimize hypoglycemia events <54 mg/dl.

Aims: The aim of this analysis is to examine the expected relationship between the coefficient of glycemic variation and time in range (%TIR), time below range (%TBR) and time above range (%TAR) in continuous glucose monitoring systems.

Methods: We analysed a subset of 71 patients with type 1 diabetes followed at our endocrinology outpatient clinic using a continuous glucose monitor system that uploads data to a database accessible for clinicians. 16 out of 71 patients were excluded, 11 patients because they had less than 70% of data captured by the sensor in the previous 2 weeks and 5 patients because they had a diagnosis within the previous year. A bivariate analysis was performed to evaluate the relation between the %CV and %TIR, %TBR and %TAR in 55 patients. Time in range is defined as between 70 and 180 mg/dl. Furthermore, a bivariate analysis was performed to evaluate the relation between %CV and the subgroup time below 54 mg/dl (%TB 54).

Results: Patients were between 22 and 66 years old (mean 43, SD 12) and 42% were male. The %CV showed a strong positive correlation and statistically significant with %TBR (r=0.708, P < 0.0001) and a weak negative correlation, but statistically significant with %TIR (r=-0.398, P=0.003). There was no correlation between %CV and %TAR. Both correlations are independent of age and sex. Moreover, the %CV showed a strong positive correlation and statistically significant with %TB 54 (r=0.664, P < 0.0001).

Conclsions: The coefficient of glycemic variation is an important metric to evaluate the risk of hypoglycemia, in our analysis it is closely correlated with time below 70 mg/dl and also with time below 54 mg/dl. These results are consistent with results from other studies. Although weak it is important to note the negative correlation between coefficient of glycemic variation and time in range, as the latest is an indicator for evaluating the efficacy of glycemic control and predicting diabetic complications. Our analysis highlights the importance of %CV in the management of type 1 diabetic patients.