To examine the association between treatment-achieved HbA_1c values and incidence of both coronary artery disease (CAD) and severe eye disease with different diabetes treatments.

Associations of treatment-achieved HbA_1c were investigated in various treatment groups [diet only; insulin; sulphonylurea (SU) alone; SU with glinides; and antihyperglycaemic agents other than glinides, SU or insulin] taken from a nationwide claims database of 14,633 Japanese diabetes patients. Cox’s regression analysis examined risks over a 5.1-year follow-up.

A significant linear trend was associated with HbA_1c levels and CAD events in the diet-only group, and CAD risks were significantly higher in insulin and SU groups with HbA_1c ≤ 7.0% and > 8.0% than in the diet-only group with HbA_1c ≤ 7.0%. In contrast to CAD, a linear association was observed regardless of treatment modality between achieved HbA_1c levels and risk of severe diabetic eye disease, but with no significant difference in eye disease risk between groups with HbA_1c ≤ 7.0% and 7.1–8.0% in those treated with either SU alone, SU with glinides, or insulin.

These findings suggest that the relationship between treatment-achieved HbA_1c and incidence of both CAD and severe diabetic eye disease differed according to treatment, based on a large-scale real-life database. More research is now needed to confirm these findings and to further investigate the underlying mechanisms.