Baseline Glycated Hemoglobin Values Predict the Magnitude of Glycemic Improvement in Patients with Type 1 and Type 2 Diabetes: Subgroup Analyses from the DIAMOND Study Program

The DIAMOND study demonstrated that the addition of real-time continuous glucose monitoring (rtCGM) effectively lowers glycated hemoglobin (HbA(1c)) in patients with type 1 (T1D) and type 2 diabetes (T2D), treated with multiple daily injections (MDI). This post hoc analysis investigated whether DIAMOND study participants at progressively higher baseline HbA(1c) levels benefit from using rtCGM. We examined outcomes data from a large, randomized, controlled trial of MDI-treated participants with T1D (N = 158) and T2D (N = 158), comparing monitoring by rtCGM versus self-monitoring of blood glucose (SMBG). The primary outcome was the magnitude of HbA(1c) reductions among study participants within elevated baseline HbA(1c) levels (≥8.0%–10.0%, ≥8.5%–10.0%, and ≥9.0%–10.0%). Analyses were performed on three subgroups: T1D, T2D, and combined T1D/T2D. The full T1D analysis population had a mean baseline HbA(1c) value of 8.6 ± 0.6% (range 7.5%–9.9%), randomized to rtCGM (n = 105) or control (n = 53). The full T2D analysis population had a mean baseline HbA(1c) value of 8.5 ± 0.6% (range 7.5%–9.9%), randomized to rtCGM (n = 79) or control (n = 79). Participants had improvements in glycemic status regardless of monitoring method. In the three subgroups, the change in HbA(1c) was significantly greater in rtCGM participants compared to SMBG at all predefined baseline HbA(1c) levels at 12 and 24 weeks. Among the rtCGM participants, the change in HbA(1c) was numerically greatest at the highest baseline HbA(1c) subgroup (≥9.0%). Participants with elevated baseline HbA(1c) had improvements in glycemic status regardless of monitoring method. However, the magnitudes of improvements appeared greater among participants using rtCGM.