This slide shows data from other study where risk of coronary heart disease mortality was related to base line levels of risk factors (in this slide to systolic blood pressure). This would imply that blood pressure has a more profound effect in non-diabetic subjects. There are two things which are pointing out:

a). The access risk of diabetes is nothing to do with blood pressure (somebody with 120 systolic blood pressure has 4 times higher risk in mortality if he has diabetes). So, the diabetes is the independent risk factor.

b). I want to contrast the relative risk increase with blood pressure in diabetes and absolute risk increase.