Diabetes Complications and Related Comorbidities Impair the Accuracy of FreeStyle Libre, a Flash Continuous Glucose Monitoring System, in Patients with Type 2 Diabetes

Abstract

Background

Although flash continuous glucose monitoring systems (FCGM) accuracy has been extensively studied in diabetes, its accuracy is still not fully evaluated in type 2 diabetes (T2D) patients in real-world settings. In the present study, we aim to assess the effects of diabetes complications and related comorbidities on FCGM accuracy in T2D patients with diabetes complications and related comorbidities in the real world.

Methods

FCGM data were collected at eight-time points daily (3 AM, 7 AM, 9 AM, 11 AM, 1 PM, 5 PM, 7 PM, and 9 PM) from 742 patients with T2D and compared with simultaneous fingertip capillary blood glucose (reference blood glucose, REF), and the difference was evaluated using Parkes error grid (PEG), surveillance error grid (SEG), and logistic regression analysis.

Results

In total, 25,579 FCGM/REF data pairs were included in the study. The FCGM values were lower than the paired REF values in 75% of the pairs. The maximum bias (−23.0%) and maximum mean absolute relative difference (24.5%) were observed at 3 AM among eight-time points. SEG analysis also demonstrated the highest percentage of paired readings in moderate and great risk zone (C and D) at 3 AM than PEG analysis (7.33% vs 0.43%, P<0.001). According to the SEG classification, hypoglycemia, infection, diabetic foot, diabetic ketoacidosis, and hypertension were independent risk factors that impaired FCGM accuracy in patients.

Conclusion

FCGM commonly underestimates blood glucose levels. Compared with PEG, SEG analysis seems more conducive to the analysis of FCGM performance. The present data highlights the impairment of diabetes complications and related comorbidities on the FCGM accuracy in T2D patients.

Keywords:

• flash continuous glucose monitoring system
• type 2 diabetes
• surveillance error grid
• Parkes error grid
• diabetes complications

Data Sharing Statement

The data used to support the findings of this study may be released upon application to the Second Affiliated Hospital of Guangzhou Medical University, which can be contacted through Prof. Tao Du (email: [email protected]).

Disclosure of Ethical Statements

This study was approved by the academic ethics review boards of the hospital, the Second Affiliated Hospital of Guangzhou Medical University. Informed consents were obtained from all patients.

Acknowledgments

The authors thank all participants in this study. This work was supported by grants from the Guangzhou Municipal Science and Technology Project (201607010036), and the Guangdong Basic and Applied Basic Research Foundation (2020A1515010060, 2021A1515011333). Xiaofang Wen, Nan Zeng, and Ningbo Zhang are co-first authors for this study.

Disclosure

The authors declare no conflicts of interest in this work.