Patients with type 1 diabetes had double the risk of death after undergoing CABG compared with a group that did not have diabetes, according to an observational, nationwide population-based cohort study.
There was also a small but statistically significant increase in the risk of death among patients with type 2 diabetes compared with patients without diabetes.
Lead researcher Martin J. Holzmann, MD, PHD, of Karolinska University Hospital in Stockholm, and colleagues published their findings online in the Journal of the American College of Cardiology on April 20.
Researchers noted that patients with diabetes have an increased risk of cardiovascular disease and death. They said approximately 25 percent of patients in the U.S. who undergo multivessel coronary revascularization have diabetes.
In this study, they included all patients who underwent primary isolated nonemergency CABG in Sweden between 2003 and 2013. They obtained data from the SWEDEHEART (Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) register as well as the National Patient Register, Swedish Renal Register and Statistics Sweden.
Of the 39,235 patients, 21 percent were women, and the mean age was 67. In addition, 21 percent of the patients had type 2 diabetes and 1.8 percent had type 1 diabetes. Patients with type 1 diabetes were more likely to be younger, female and have chronic kidney disease, end-stage renal disease, peripheral vascular disease and heart failure. Previous research found those comorbidities were associated with a worse prognosis in diabetic patients after undergoing CABG, according to Holzmann et al.
After a mean follow-up of 5.9 years, 21 percent of patients with type 1 diabetes had died compared with 19 percent of patients with type 2 diabetes and 17 percent of patients who did not have diabetes.
Researchers also found a significantly higher risk for all-cause mortality in patients with type 1 diabetes compared with those with type 2 diabetes. The mean duration of disease was 40.8 years in patients with type 1 diabetes and 9.6 years in patients with type 2 diabetes.
“This fact may help explain the differences seen in prognosis between the 2 subtypes of diabetes, because the duration of exposure to risk factors and comorbidities was considerably longer in patients with (type 1 diabetes) than in those with (type 2 diabetes),” the researchers wrote.