The Relationship Between HbA1c Concentration and Glycemic Variability Parameters Assessed Peripartum in Women with Type 1 Diabetes: Retrospective Study

Objective: This study aimed to analyze peripartum glycated hemoglobin (HbA1c) concentration and glycemic variability parameters using continuous glucose monitoring (CGM) in pregnant women with type 1 diabetes (T1D) treated with continuous subcutaneous insulin infusion (CSII). Material and methods: Forty-five pregnant women with T1D managed at two centers in Poland were included. CGM records from the 14 days preceding delivery were evaluated to determine glycemic variability parameters and circadian profiles, and their relationship with HbA1c measured on the day of delivery was assessed. Results: A relationship was found between HbA1c values and 24-hour glycemic variability parameters [average glycemia (rho = 0.64; p < 0.001); median glycemia (rho = 0.60; p < 0.001); SD (rho = 0.52; p < 0.001); TBR < 54 (rho = –0.38; p = 0.009); TBR < 63 (rho = –0.36; p = 0.016); TIR 63–140 (rho = –0.53; p < 0.001); TAR > 140 (rho = 0.65; p < 0.001); GMI (rho = 0.63; p < 0.001)] as well as at night 24.00–06.00 [average glycemia (rho = 0.53; p < 0.001); median glycemia (rho = 0.54; p < 0.001); SD (rho = 0.51; p < 0.001); CV (rho = 0.35; p = 0.020); TIR 63-140 (rho = –0.47; p = 0.001); TAR > 140 (rho = 0.57; p < 0.001)]. However, no correlation was found to exist during the daytime. Conclusions: Peripartum night-time glycemic variability has a greater influence on HbA1c levels than 24 hours glycemic variability in pregnant patients with T1D. This indicates the need to pay more attention to the glycemia course during the night hours and not limit the assessment of the level of glycemia control only to the overall analysis of the results available from CGM and HbA1c.