Diabetes is an established risk factor of cardiovascular disease including the coronary heart disease (CHD) and elevates the risk of cardiovascular death 2 times. Based on current evidence the risk of acquiring the CHD increases accordingly to the level of fasting blood glucose even in the prediabetic range.
In the range of 5.6-6.0 mmol/l the risk is 1.11, in the range of 6.1-6.9 mmol/l the risk is 1.17. In the range of HbA1c of 42-47 mmol/l the risk of the CHD is 1.28.
The probability of the CHD occurrence therefore does indeed increase in conjunction with the fasting blood glucose levels but the dependence is not linear.