Hemoglobin A1c as a Measure of Disease Severity and Outcome in Limb Threatening Ischemia

Abstract

Diabetes mellitus is a known risk factor in the development of peripheral vascular disease. Hemoglobin A1c (HbA1c) has been used by clinicians as a means to measure short to intermediate term glucose control in diabetics. Trials evaluating tight glucose control using HbA1c measurements have recently been conducted for several medical conditions. The goal of this study is to determine if the level of hemoglobin A1c has any effect on disease severity in diabetic patients with limb threatening ischemia. A retrospective review of all patients presentingwith limb threatening ischemia between January 1 and December 31, 2007 was conducted. All patients underwent conventional arteriography prior to intervention. Of 148 patients, 73 were diabetics with a hemoglobin A1c level performed within 3 mo of presentation. Patients were placed into high (>7) and low (<7) hemoglobin A1c groups and data was collected on type of presentation, comorbidities, anatomic level of disease, tibial artery patency, need for amputation, contralateral disease, need for an open versus an endovascular procedure, and freedom from intervention. Fisher's exact t-test was used to compare the two groups. A P value <0.05 was considered statistically significant. Thirty-six patients had HbA1c levels above 7.0 and 37 had levels below 7.0 (mean 7.64 ± 2.04, range 5.1-14.7). There were no statistically significant differences in the two groups in comorbities, average age, initial gangrene at presentation, aspirin or statin use, or smoking status. Patients in the high group were more likely to have had a previous attempt at revascularization (23 versus 11, P = 0.0049). There was no difference in the presence of contralateral disease (7versus 4, P = 0.3447) or in the number of patent tibial vessels. Patients with low HbA1c levels were more likely to have the peroneal artery affected (17 versus 8, P = 0.048). In addition, TASC II classifications of iliac and femoral popliteal disease was similar between the two groups. Freedom from intervention is depicted graphically by life table analysis. Glucose control measured by hemoglobin A1c does not appear to affect severity of disease or need for reintervention in diabetics with limb threatening ischemia. This suggests other factors related to diabetes may play a role in peripheral vascular disease. Larger, prospective studies are needed to assess the affect of glucose control in limb threatening ischemia.