Glucose Regulation Beyond HbA1c in Type 2 Diabetes Treated With Insulin: Real-World Evidence From the DIALECT-2 Cohort

Niala den Braber; Miriam M R Vollenbroek-Hutten; Kathryn M Westerik; Stephan J L Bakker; Gerjan Navis; Bert-Jan F van Beijnum; Gozewijn D Laverman

doi:10.2337/dc20-2241

Glucose Regulation Beyond HbA_1c in Type 2 Diabetes Treated With Insulin: Real-World Evidence From the DIALECT-2 Cohort

Diabetes Care. 2021 Jul 22;44(10):2238-2244. doi: 10.2337/dc20-2241. Online ahead of print.

Authors

Niala den Braber^{1

2}, Miriam M R Vollenbroek-Hutten^{3

2}, Kathryn M Westerik³, Stephan J L Bakker⁴, Gerjan Navis⁴, Bert-Jan F van Beijnum², Gozewijn D Laverman³

Affiliations

¹ Division of Nephrology, Department of Internal Medicine, Ziekenhuisgroep Twente, Almelo and Hengelo, the Netherlands n.braber@zgt.nl.
² Biomedical Signals and Systems, University of Twente, Enschede, the Netherlands.
³ Division of Nephrology, Department of Internal Medicine, Ziekenhuisgroep Twente, Almelo and Hengelo, the Netherlands.
⁴ Division of Nephrology, Department of Internal Medicine, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.

Abstract

Objective: To investigate glucose variations associated with glycated hemoglobin (HbA_1c) in insulin-treated patients with type 2 diabetes.

Research design and methods: Patients included in Diabetes and Lifestyle Cohort Twente (DIALECT)-2 (n = 79) were grouped into three HbA_1c categories: low, intermediate, and high (≤53, 54-62, and ≥63 mmol/mol or ≤7, 7.1-7.8, and ≥7.9%, respectively). Blood glucose time in range (TIR), time below range (TBR), time above range (TAR), glucose variability parameters, day and night duration, and frequency of TBR and TAR episodes were determined by continuous glucose monitoring (CGM) using the FreeStyle Libre sensor and compared between HbA_1c categories.

Results: CGM was performed for a median (interquartile range) of 10 (7-12) days/patient. TIR was not different for low and intermediate HbA_1c categories (76.8% [68.3-88.2] vs. 76.0% [72.5.0-80.1]), whereas in the low category, TBR was higher and TAR lower (7.7% [2.4-19.1] vs. 0.7% [0.3-6.1] and 8.2% [5.7-17.6] vs. 20.4% [11.6-27.0], respectively, P < 0.05). Patients in the highest HbA_1c category had lower TIR (52.7% [40.9-67.3]) and higher TAR (44.1% [27.8-57.0]) than the other HbA_1c categories (P < 0.05), but did not have less TBR during the night. All patients had more (0.06 ± 0.06/h vs. 0.03 ± 0.03/h; P = 0.002) and longer (88.0 [45.0-195.5] vs. 53.4 [34.4-82.8] minutes; P < 0.001) TBR episodes during the night than during the day.

Conclusions: In this study, a high HbA_1c did not reduce the occurrence of nocturnal hypoglycemia, and low HbA_1c was not associated with the highest TIR. Optimal personalization of glycemic control requires the use of newer tools, including CGM-derived parameters.