Table 5

Estimate of A1C for a given TIR level based on type 1 diabetes and type 2 diabetes studies

Beck et al. (26) (n = 545 participants with type 1 diabetes)Vigersky and McMahon (27) (n = 1,137 participants with type 1 or type 2 diabetes)
TIR 70–180 mg/dL (3.9–10.0 mmol/L)A1C, % (mmol/mol)95% CI for predicted A1C values, %TIR 70–180 mg/dL (3.9–10.0 mmol/L)A1C, % (mmol/mol)
20%9.4 (79)(8.0, 10.7)20%10.6 (92)
30%8.9 (74)(7.6, 10.2)30%9.8 (84)
40%8.4 (68)(7.1, 9.7)40%9.0 (75)
50%7.9 (63)(6.6, 9.2)50%8.3 (67)
60%7.4 (57)(6.1, 8.8)60%7.5 (59)
70%7.0 (53)(5.6, 8.3)70%6.7 (50)
80%6.5 (48)(5.2, 7.8)80%5.9 (42)
90%6.0 (42)(4.7, 7.3)90%5.1 (32)
Every 10% increase in TIR = ∼0.5% (5.5 mmol/mol) A1C reductionEvery 10% increase in TIR = ∼0.8% (8.7 mmol/mol) A1C reduction
  • The difference between findings from the two studies likely stems from differences in number of studies analyzed and subjects included (RCTs with subjects with type 1 diabetes vs. RCTs with subjects with type 1 or type 2 diabetes with CGM and SMBG).