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Objective: To examine the effect of socioeconomic status on outcome in patients undergoing vascular surgery.
Methods: Hospital discharge data from the Nationwide Inpatient Sample (NIS) were used to identify inpatient hospital visits from 2003-2005 in which abdominal aortic aneurysm (AAA) repair or carotid endarterectomy (CEA) were performed. Procedures were identified by procedural ICD-9 coding: 38.12, 38.34, 38.44, 38.64, 39.71, 39.79, and 39.25. Socioeconomic status (SES) was defined using median household income per patient zip code and grouped into quartiles for each year with the upper 2 quartiles (Q3 and Q4) combined for analysis. Primary payer was grouped into four classes for analysis: Insurance (including private and other), Medicare, Medicaid, and no insurance. Evaluated outcomes included total charges, length of stay (LOS), and in-hospital mortality. Outcomes were risk adjusted utilizing 29 of the 30 Elixhauser comorbidities as well as age, race, gender, and primary payer. Associations between SES and outcomes were evaluated using linear or logistic regression using methods for complex surveys. LOS and total charge data were log transformed for analysis, and comparisons were back-transformed for reporting.
Results: Utilizing the NIS database, we identified 206,658 hospital visits in which AAA repair was performed and 391,658 visits in which CEA was performed. In the AAA group, the mean age was 66.6 years and 28.6% were female. In the CEA group, the mean age was 71.1 years and 42.5% were female. Among the AAA group, when controlled for age, the lowest quartile (Q1) showed 9% longer LOS (95% CI: 5%-13%, p<0.0001) and 20% higher odds of mortality (OR=1.20, 95% CI: 1.07-1.34, p=0.0014) compared to the upper two quartiles together (Q3 & Q4). Similarly, for CEA, Q1 showed 9% longer LOS (95% CI: 5%-12%, p<0.0001) and 33% higher odds of mortality (OR=1.33, 95% CI: 1.06-1.66, p=0.0139) versus Q3 & Q4 together, when controlled for age. A significant difference in LOS persisted in both groups after additionally controlling for gender, race, primary payer and the Elixhauser comorbidities, with Q1 consistently showing longer LOS compared to Q3 & Q4 together
Conclusion: Patients in the lowest quartile of income estimated by zip code showed a significantly longer length of stay and higher mortality after undergoing CEA and AAA repair. Socioeconomic status may affect key outcomes in vascular surgery.