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

OBJECTIVE To investigate glucose variations associated with HbA_1c in insulin treated patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS Patients included in the Diabetes and Lifestyle Cohort Twente (DIALECT)-2 (n=79) were categorized in three HbA_1c categories: low, intermediate and high (≤ 53; 54–62 and ≥ 63 mmol/mol or ≤ 7, 7.1–7.8, ≥ 7.9%). 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.