Risk factors and mortality in dialysis patients with abdominal aortic aneurysm: A retrospective cohort study

In the general population, abdominal aortic aneurysm (AAA) is synonymous with vascular disease and associated with increased mortality. Vascular disease is common in end-stage renal disease (ESRD) patients on dialysis, but there is limited information on AAA in this population. To address this issue, we queried the United States Renal Data System for risk factors associated with a diagnosis of AAA as well as the impact of AAA on ESRD patient survival. Incident dialysis patients from 2005 to 2014 with AAA and other clinical comorbidities were identified using ICD-9 and ICD-10 codes. Time to death was defined using the time from the start of dialysis to the date of death or to December 31, 2015. Cox proportional hazards (CPH) modeling was used to determine the adjusted hazard ratio (aHR) and 95% confidence intervals (CI) for death. From a total cohort of 820,826, we identified 21,631 subjects with a diagnosis of AAA. When compared to patients without AAA, AAA patients were older and more likely to be of white race and male gender, have a higher mean Charlson comorbidity index (CCI), have hypertension as the ESRD etiology, and use tobacco. Although a bivariate CPH model showed that AAA patients had an increased mortality risk compared to patients without the diagnosis, in the final CPH model, AAA patients had a decreased risk of mortality (aHR = 0.83, 95% CI 0.81-0.84) due to confounding with age. These results suggest that AAA is not associated with increased risk of death in ESRD patients after controlling for various demographic and clinical risk factors.