Chronic Kidney Disease Class Predicts Mortality after Abdominal Aortic Aneurysm Repair in Propensity-Matched Cohorts from the Medicare Population

Abstract

Chronic renal insufficiency (CKD) is a predictor of death after abdominal aortic aneurysm (AAA) repair. However, few studies are adequately powered to stratify risk by CKD severity. The goal of this study was to assess the effect of CKD severity on survival after AAA repair. All patients who underwent open or endovascular AAA repair from 2006 to 2007 were retrospectively identified in the Medicare database and stratified by CKD stage into 3 groups: normal (CKD 0-1), moderate (CKD 2-4), and severe (CKD 5-6). Propensity matching (30:1) of known risk factors was performed. The primary outcome was death; secondary outcomes included hospital length of stay (LOS) and cost. We identified 47,715 patients (96.7% normal, 1.88% moderate, 1.65% severe). After propensity matching, there was no difference in comorbidities between cohorts. The 30-day mortality was significantly higher in the moderate (5.7%) vs normal (2.5%, P < 0.0001) and severe (9.9%) vs normal (1.8%; P < 0.0001) groups. The 3-year survival favored the normal cohort (80%) vs moderate (64%; P < 0.0001) and 81% vs severe (44%; P < 0.0001). Hospital LOS increased with CKD severity (4.4 days normal vs 6.5 moderate, P < .0001; 4.7 normal vs 9.1 days severe, P < .0001) as did cost ($77,275 normal vs $97,410 moderate, P < .0001; $73,273 normal vs $113,863 severe, P < .0001). CKD severity is an important predictor of perioperative mortality and long-term survival after AAA repair in propensity matched cohorts. The fivefold increase in 30-day mortality and mere 44% 3-year survival suggest that elective AAA repair is contraindicated in most patients with severe CKD.