Glycaemic control and excess risk of major coronary events in patients with type 2 diabetes: a population-based study

The purpose of the study was to investigate the excess risk of acute myocardial infarction (AMI) and death from coronary artery disease (coronary heart disease, CHD) in relation to age, level of glycaemic control and renal complications in patients with type 2 diabetes.

A total of 431 579 patients with type 2 diabetes mellitus registered in the Swedish National Diabetes Register from 1 January 1998 to 31 December 2012, and 2 173 620 controls from the general population were included. Cox regression was used to study the excess risk of AMI and CHD.

During follow-up of 5.1 years in the diabetes group and 5.4 years in the control group, 36 124 (8.4%) and 115 712 (5.3%) CHD events were registered, with corresponding incidence rates/1000 person-years of 14.64 (95% CI 14.49 to 14.79) and 8.73 (95% CI 8.68 to 8.78), respectively. The HR after adjustment for sex and age was 1.67 (1.65-1.69) which was reduced to 1.42 (1.41-1.44) with further adjustment for level of education, country of birth, diabetes duration and comorbidities. The multivariable-adjusted HR for AMI and CHD death with a time-updated glycated haemoglobin level of 6.9% or lower (≤52 mmol/mol) together with normoalbuminuria and estimated glomerular filtration rate ≥60 mL/min for patients with diabetes compared with controls was 0.95 (95% CI 0.92 to 0.98, p<0.001).

In this study, the excess risk of AMI and CHD death was higher for patients with type 2 diabetes compared with controls but converged to that in the general population in patients with on-target HbA1c levels and without renal complications.