Insulin Dependence is Associated with Poor Long-Term Outcomes Following AAA Repair.

Background: While prior studies have confirmed the protective effect of diabetes on abdominal aortic aneurysm (AAA) development, much less is known about the effect of diabetes, and in particular insulin dependence, on outcomes following AAA repair. In this study, we aim to evaluate the role of insulin-dependent diabetes on short-term and long-term outcomes following open and endovascular AAA repair.

Methods: The Vascular Implant Surveillance and Interventional Outcomes Network (VISION), a registry linking the Vascular Quality Initiative (VQI) data with Medicare claims, was queried for patients who underwent open or endovascular AAA repair from 2011 to the present. Exclusion criteria were unknown diabetes status, prior aortic intervention, maximum aneurysm diameter <45 mm at presentation, and Medicare Advantage coverage due to inconsistent follow-up. Patients were stratified based on diabetes status (no diabetes versus diabetes) and insulin dependence (no diabetes or non-insulin-dependent diabetes versus insulin-dependent diabetes).

Results: Of the 38,437 cases in the VISION endovascular aortic aneurysm (EVAR) and open aortic aneurysm repair (OAR) databases, 21,943 met inclusion criteria. Perioperative outcomes after OAR were comparable between diabetic and nondiabetic patients. However, diabetic patients undergoing EVAR were significantly more likely to have a postoperative myocardial infarction (1.0% vs 0.6%, P = 0.04) and have a 30-day readmission (10.9% vs 8.8%, P < 0.001). Insulin-dependent diabetic patients were more likely to require a 30-day readmission after OAR (24.5% vs 13.5%, P = 0.02) and EVAR (15.1% vs 9.0%, P < 0.001); however, only insulin-dependent diabetes mellitus (IDDM) patients undergoing EVAR experienced higher rates of postoperative myocardial infarction (1.9% vs 0.7%, P < 0.01). After propensity score matching, patients with IDDM undergoing EVAR were additionally at increased risk of mortality at 1-year, 3-year, and 5-year follow-up with the highest risk occurring at the 1-year mark (hazard ratio 1.79, P < 0.0001), while IDDM patients undergoing OAR were only at a significantly increased risk of mortality at 5-year follow-up (hazard ratio 1.90, P = 0.01).

Conclusions: Patients with insulin-dependent diabetes have greater than 14% one-year mortality following open or endovascular aneurysm repair, compared to 8% for all others. Our findings raise questions about whether insulin-dependent diabetics should have a higher size threshold for prophylactic repair, although further studies are needed to address this question and consider the influence of glycemic control on these outcomes.