Continuous insulin monitoring does not raise hospital costs

Patients with diabetes whose glucose is continually monitored after coronary bypass artery graft surgery do not incur higher medical costs despite the additional testing, Penn State Diabetes Center researchers report.

"Increasing evidence suggests that sickness and death can be reduced among surgical patients with diabetes if we provide tighter control of blood glucose just before, during and after surgery," said Robert A. Gabbay, associate professor of medicine, Penn State College of Medicine, co-director, Penn State Diabetes Center. "Our study shows that continuous insulin monitoring and involvement of an endocrinologist in the patients' care do not increase the cost of treating a patient with diabetes undergoing coronary artery bypass graft surgery."

The study, titled "Improved perioperative glycemic control by continuous insulin infusion under supervision of an endocrinologist does not increase costs in patients with diabetes," was published in the April issue of the journal Endocrine Practice.

Coronary artery bypass graft (CABG) surgery is a standard treatment for advanced coronary disease in people with diabetes. In the procedure, veins are removed from the legs or arms and used to create a bypass around a blocked area in a coronary artery. As many as 25 percent of adult CABG procedures in the U.S. are performed on patients with diabetes. Morbidity, death and risk of deep sternal would infections are higher in patients with diabetes who undergo CABG surgery than in those without diabetes. Evidence suggests that those poor outcomes are due in part to hyperglycemia, or too much glucose in the blood, before, during and after surgery.

For the study, Gabbay and his team developed an Insulin infusion Glycemic Control Protocol (IGCP). The protocol established a set of steps that medical staff followed when treating the 107 patients with diabetes who underwent CABG surgery at Penn State Hershey Medical Center in the year 2000. Before surgery, patients with diabetes were started on an IV insulin infusion with glucose monitoring every one to two hours. Their goal was to maintain glucose levels between 120 and 200 milligrams per deciliter (mg/dl) of blood (the safe, or "target" range for people with diabetes) throughout the patient's surgery and for at least 48 hours after. The protocol required training for and cooperation from surgical teams, anesthesiologists and nursing staff. As part of the protocol, an endocrinologist assisted with glucose management.

The patients admitted under the IGCP, were compared to 81 patients with diabetes who underwent CABG surgery at the Medical Center in 1999 who were cared for using conventional methods, with glucose monitoring every four to six hours.

The IGCP group showed significantly better glycemic control than the conventional group. Average glucose for patients in the protocol was 183.5 mg/dl. Patients receiving conventional treatment had mean glucose of 241.7. Overall cost of treatment for patients on the IGCP was $21,076 compared to $21,422 for patients in conventional treatment.

Although the data was not statistically significant due to small sample size, patients on the IGCP showed a trend toward shorter length of stay in the hospital and fewer deep sternal wound infections compared to patients with conventional treatment. This supports earlier research showing that better glycemic control improves outcomes for patients with diabetes. Although the study suggests it, it was not clear that expenses incurred by the protocol -- insulin infusions, frequent glucose monitoring and the need for an endocrinologist consultation -- were offset by the avoidance of costly complications like treatment for infection.

"Although more and more evidence supports the role of better glycemic control in intensive care situations for people with diabetes, most hospitals are not currently providing tight glycemic control. The likely reason is concern about the costs," Gabbay said. "Our hope is that more centers will be willing to incorporate a protocol like the one we used in this study, based on our findings that it will not incur additional costs."