Objective: Aneurysmal subarachnoid hemorrhage (aSAH) has devastating consequences. The association between higher institutional volumes and improved outcomes for aSAH patients has been studied extensively. However, the literature exploring patterns of transfer in this context is sparse. Expansion of the endovascular workforce has raised concerns about the decentralization of care, reduced institutional volumes, and worsened patient outcomes. In this paper, the authors explored various patient and hospital factors associated with the transfer of aSAH patients by using a nationally representative database.
Methods: The 2013 and 2014 years of the National Inpatient Sample (NIS) were used to define an observational cohort of patients with ruptured brain aneurysms. The initial search identified patients with SAH (ICD-9-CM 430). Those with concomitant codes suggesting trauma or other intracranial vascular abnormalities were excluded. Finally, the patients who had not undergone a subsequent procedure to repair an intracranial aneurysm were excluded. These criteria yielded a cohort of 4373 patients, 1379 of whom had undergone microsurgical clip ligation and 2994 of whom had undergone endovascular repair. The outcome of interest was transfer status, and the NIS data element TRAN_IN was used to define this state. Multiple explanatory variables were identified, including age, sex, primary payer, median household income by zip code, race, hospital size, hospital control, hospital teaching status, and hospital location. These variables were evaluated using descriptive statistics, bivariate correlation analysis, and multivariable logistic regression modeling to determine their relationship with transfer status.
Results: Patients with aSAH who were treated in an urban teaching hospital had higher odds of being a transfer (OR 2.15, 95% CI 1.71-2.72) than the patients in urban nonteaching hospitals. White patients were more likely to be transfer patients than were any of the other racial groups (p < 0.0001). Moreover, patients who lived in the highest-income zip codes were less likely to be transferred than the patients in the lowest income quartile (OR 0.78, 95% CI 0.64-0.95). Repair type (clip vs coil) and primary payer were not associated with transfer status.
Conclusions: A relatively high percentage of patients with aSAH are transferred between acute care hospitals. Race and income were associated with transfer status. White patients are more likely to be transferred than other races. Patients from zip codes with the highest income transferred at lower rates than those from the lowest income quartile. Transfer patients were preferentially sent to urban teaching hospitals. The modality of aneurysm treatment was not associated with transfer status.
Keywords: endovascular repair; epidemiology; intracranial aneurysm; microsurgical clip ligation; subarachnoid hemorrhage; teaching hospital; vascular disorders.