The rate of diabetic coronary artery bypass graft patients has increased more than fivefold in recent decades, and these patients are more likely to have worse outcomes and higher treatment costs, a study showed.

The percentage of patients who had diabetes among all those undergoing coronary artery bypass grafting (CABG) increased from 7% in the 1970s to 37% in the 2000s, according to a database study of 55,501 patients operated on at the Cleveland Clinic.

Dr. Sajjad Raza Frontline Medical News/Martin Allred

Dr. Sajjad Raza

Patients were identified and preoperative, operative, and postoperative variables were identified, resulting in 45,139 nondiabetic patients assessed and 10,362 diabetic patients (defined as those diabetic patients pharmacologically treated with either insulin or an oral agent) evaluated. The endpoints assessed were in-hospital adverse outcomes as determined by the Society of Thoracic Surgeons National Database, in-hospital direct technical costs, and time-related mortality, according to Dr. Sajjad Raza and his colleagues at the Cleveland Clinic in the August issue of the Journal of Thoracic and Cardiovascular Surgery (150:294-301).

Compared with nondiabetics, diabetic patients undergoing CABG were older and were more likely to be overweight, to be women, and to have a history of heart failure, peripheral arterial disease, carotid disease, hypertension, renal failure, stroke, and advanced coronary artery disease. Over time, the cardiovascular risk profile of the entire population changed, becoming even more pronounced for all patients, but more so for diabetics.

Overall long-term survival at 6 months and at 1, 5 10, 15, and 20 years for diabetic patients was 95%, 94%, 80%, 54%, 31%, and 18%, respectively, compared with 97%, 97%, 90%, 76%, 59%, and 42% for nondiabetic patients, a significant difference at P <.0001.

Propensity matching of similar diabetic and nondiabetic patients showed that deep sternal wound infection and stroke occurred significantly more often in diabetics, although there were no significant differences in cost remaining after matching, even though the length of stay greater than 14 days remained higher for diabetic patients.

Among diabetics, overall survival at 6 months and at 1, 5, 10, 15, and 20 years after CABG was 95%, 94%, 80%, 54%, 31%, and 18%, respectively, compared with overall survival in nondiabetics at 97%, 97%, 90%, 76%, 59%, and 42%, respectively, a significant difference (P <.0001).

“Although long-term survival after CABG is worse in diabetics and high-risk nondiabetics, it is important to note that, in general, high-risk patients reap the greatest survival benefit from CABG. Moreover, using surgical techniques that are associated with better long-term survival after CABG in diabetics could further enhance this survival benefit,” Dr. Raza and his colleagues wrote.

“Diabetes is both a marker for high-risk, resource-intensive, and expensive care after CABG and an independent risk factor for reduced long-term survival,” they added. “Diabetic patients and those with a similar high-risk profile set to undergo CABG should be made aware that their risks of postoperative complications are higher than average, and measures should be taken to reduce their postoperative complications,” Dr. Raza and his colleagues concluded.

The authors reported that they had no relevant conflicts of interest.