Preoperative oral glucose tolerance testing in vascular surgery patients: Long-term cardiovascular outcome
Background: Diabetes mellitus (DM) is an important risk factor in vascular surgery patients, influencing late outcome. Screening for diabetes is recommended by fasting glucose measurement. Oral glucose tolerance testing (OGTT) could enhance the detection of patients with impaired glucose tolerance (IGT) and DM. Aim: To assess the additional value of OGTT on top of fasting glucose levels in vascular surgery patients to predict long-term cardiovascular outcome. Methods: A total of 404 patients without signs or histories of IGT (plasma glucose 7.8-11.1 mmol/L) or DM (glucose ≥11.1 mmol/L) were prospectively included and subjected to OGTT. Cardiac risk factors were noted. Primary outcome was the occurrence of late cardiovascular events (composite of cardiovascular death, angina pectoris, myocardial infarction, percutaneous coronary intervention/coronary artery bypass grafting, or cerebral vascular accident/transient ischemic attack), and secondary outcome included all-cause and cardiovascular mortality rates, in survivors of vascular surgery. Median follow-up was 3.0 (interquartile range 2.4-3.8) years. Results: Impaired glucose tolerance (n = 104) and DM (n = 43) were detected by fasting glucose levels in 26 (25%) and 12 (28%) patients, and by OGTT in 78 (75%) and 31 (72%) patients, respectively. During follow-up, 131 patients experienced a cardiovascular event. With multivariable analysis, patients with IGT showed a significant increased risk for cardiovascular events (hazard ratio 2.77, 95% CI 1.83-4.20) and mortality (hazard ratio 2.06, 95% CI 1.03-4.12). Patients with DM showed a nonsignificant increased risk for cardiovascular events. Conclusion: Vascular surgery patients with IGT or DM detected by preoperative OGTT have an increased risk of developing cardiovascular events and mortality during long-term follow-up. It is recommended that nondiabetic vascular surgery patients should be tested for glucose regulation disorders before surgery.