Survival following coronary artery bypass grafting (CABG) in patients with diabetes

This study investigated long-term survival in patients with type 1 and type 2 diabetes following coronary artery bypass grafting (CABG).  The study concluded that patients with type 1 diabetes had more than double the long-term risk of death after CABG compared with patients without diabetes. The long-term risk of death in patients with type 2 diabetes was only slightly increased. 

Coronary artery bypass grafting (CABG) is a type of surgery that improves blood flow to the heart. Surgeons use CABG to treat people who have severe coronary artery disease. This is a disease in which a fatty substance called plaque builds up inside the coronary arteries. These arteries supply blood to the heart. During CABG, a healthy artery from the body is connected to the blocked artery. This newly-connected artery creates a new path to the heart.

Patients with diabetes have an increased risk of negative outcomes after CABG. Previous studies have reported long-term survival in relation to treatment with or without insulin. However survival in relation to the type of diabetes has not been reported.

The current study examined long-term survival in patients with type 1 (T1D) and type 2 (T2D) diabetes following CABG.  39,235 patients who underwent CABG were included in the study, of whom 725 had T1D and 8,208 had T2D. Patients were monitored for about 6 years following CABG. Data was collected on date and cause of death.

During the follow-up of approximately 6 years, 17% of the participants died. Among patients with T1D, 21% died and among patients with T2D, 19% died.  The risk of death was twice as likely in patients with T1D compared with patients without diabetes. The risk for those with T2D increased by 11%. 

The study concluded that patients with T1D had more than double the long-term risk of death after CABG compared with patients without diabetes. The long-term risk of death in patients with T2D was only slightly increased. 

There may have been a misclassification of those deemed not to have diabetes, as it has been shown that a large number of patients with heart problems also have undetected diabetes. 

Discuss with your doctor any concerns about CABG.