VIENNA — An oral glucose tolerance test identifed impaired glucose hemostasis in patients awaiting elective noncardiac vascular surgery more effectively than did a fasting plasma glucose test.
It's important to screen these patients for diabetes and impaired glucose tolerance because these are common complications in patients awaiting vascular surgery. The prevalence of diabetes was 11% in a group of 404 patients from one medical center, Dr. Martin Dunkelgrun and associates reported in a poster at the annual congress of the European Society of Cardiology. About three-quarters of the affected patients would have been missed if oral glucose tolerance tests (OGTT) had not been done, Dr. Dunkelgrun said in an interview.
“An OGTT should be routinely done for all patients scheduled for elective, noncardiac, vascular surgery,” said Dr. Dunkelgrun, a researcher at Erasmus University, Rotterdam, the Netherlands.
The prospective study included 404 patients with no history of diabetes or impaired glucose hemostasis who were scheduled for elective, noncardiac vascular surgery at Erasmus during November 2004-May 2007. Their average age was 68 years, and 74% were men.
The OGTT results identified 104 patients (26%) with impaired glucose hemostasis based on a plasma glucose of at least 7.8 mmol/L after the glucose challenge; 43 patients (11%) were diagnosed with diabetes, based on a serum glucose level of at least 11.1 mmol/L after glucose challenge. This shows the high prevalence rate for diabetes in vascular surgery patients, Dr. Dunkelgrun said.
Only 26 of the 104 patients with impaired glucose hemostasis (25%) and 12 of the 43 with diabetes (28%) would have been correctly diagnosed based on their fasting glucose level. Many physicians measure only the fasting plasma glucose level because an OGTT takes more time and costs more, he said.
The study also tallied the number of patients with ECG signs of coronary ischemia. Higher rates of ischemia and cardiovascular death were found in patients with diabetes or impaired glucose hemostasis. In a multivariate analysis that controlled for age, gender, renal failure, hypertension, hypercholesterolemia, and other clinical conditions, patients with diabetes had a more than threefold increased risk of having cardiac ischemia after surgery than did patients without diabetes, a significant difference. Patients with diabetes also had a 2.5-fold increased risk of cardiovascular death during the first 30 days following their surgery, but this difference was not significant.
Patients with diabetes require more careful monitoring and tighter glucose control while hospitalized for vascular surgery to reduce their cardiac risk, the investigators concluded.