Comparison of conventional measures of glucose control versus the area under the curve from a continuous glucose monitoring device in critical care patients

Introduction

In critical illness, hyperglycemia is a frequent complication resulting from metabolic and hormonal changes. Recent findings suggest increased glycemic variability may confer a strong independent risk of mortality in the critically ill [1]. Conventional measurements of glucose control include morning glucose, mean daily glucose, percentage of glucose readings in the goal range, and the hyperglycemic index (HGI) [2]. The objective of this study was to determine the most appropriate method for assessing glycemic control in cardiovascular (CV) surgery patients.

Methods

Data were obtained from a continuous glucose monitoring system (Medtronic CGMS^® System Gold™; Medtronic Diabetes, Northridge, CA, USA) database containing continuous glucose monitoring system, fingerstick, and morning laboratory blood glucose values from adult CV ICU patients. A total of 23 patients contributed to the dataset. The area under the curve every 24 hours was calculated to determine the HGI. The mean and median daily glucose, percentage of glucose readings within and above the goal range (80 to 115 mg/dl) and the mean morning glucose were calculated. Statistical analysis was performed utilizing Spearman's rho correlation to determine which measurement of glucose control correlates best with the HGI. The HGI served as the comparator group, as it is a validated and comprehensive method of assessing glucose control over time.

Results

See Table 1.

Table 1 abstract P125

Conclusion

Mean glucose was the most reflective and practical method for determining glycemic control in critically ill CV surgery patients. The morning glucose correlated the least with the HGI, demonstrating morning glucose may not be the most appropriate method to define glycemic control.