Interfacility transfer and mortality for patients with ruptured abdominal aortic aneurysm

Abstract

Objective: Patients receiving interfacility transfer to a higher level of medical care for ruptured abdominal aortic aneurysms (rAAAs) are an important minority that are not well characterized and are typically omitted from outcomes and quality indicator studies. Our objective was to compare patients transferred for treatment of rAAAs with those treated without transfer, with particular emphasis on mortality and resource utilization.

Methods: We linked longitudinal data from 2005 to 2010 Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases and Emergency Department Databases from California, Florida, and New York. Patients were identified using International Classification of Diseases-Ninth Revision-Clinical Modification codes. Our main outcome variables were mortality, length of stay, and cost. Data included discharge information on the transfer-out and transfer-in hospital. We used univariate and multivariate analysis to identify variables independently associated with transfer and in-hospital mortality.

Results: Of 4439 rAAA patients identified with intent to treat, 847 (19.1%) were transferred before receiving operative repair. Of those transferred, 141 (17%) died without undergoing AAA repair. By multivariate analysis, increasing age in years (odds ratio [OR] 0.98; 95% confidence interval [CI], 0.97-0.99; P < .001), private insurance vs Medicare (OR, 0.62; 95% CI, 0.47-0.80; P < .001), and increasing comorbidities as measured by the Elixhauser Comorbidity Index (OR, 0.90; 95% CI, 0.86-0.95; P < .001) were negatively associated with transfer. Weekend presentation (OR, 1.23; 95% CI, 1.02-1.47; P = .03) was positively associated with transfer. Transfer was associated with a lower operative mortality (adjusted OR, 0.81; 95% CI, 0.68-0.97; P < .02) but an increased overall mortality when including transferred patients who died without surgery (OR, 1.30; 95% CI, 1.05-1.60; P = .01). Among the transferred patients, there was no significant difference in travel distance between those who survived and those who died (median, 28.7 vs 25.8 miles; P = .07). Length of stay (median, 10 vs 9 days; P = .008), and hospital costs ($161,000 vs $146,000; P = .02) were higher for those transferred.

Conclusions: The survival advantage for patients transferred who received treatment was eclipsed by increased mortality of the transfer process. Including 17% of transferred patients who died without receiving definitive repair, mortality was increased for patients transferred for rAAA repair compared with those not transferred after adjusting for demographic, clinical, and hospital factors. Transferred patients used significantly more hospital resources. Improving systems and guidelines for interfacility transfer may further improve the outcomes for these patients and decrease associated hospital resource utilization.