Subarachnoid Hemorrhage Patients (2013)

Prompt and proper management of aneurysmal subarachnoid hemorrhage (SAH) dramatically improves patient outcomes, as evidenced by a number of measures.1,2 It is well established that high-volume specialized centers provide superior treatment for SAH.3,4 Many providers, however, have been unclear about the safety of transferring critically ill patients from low-volume community hospitals to these specialized centers. In 2 separate independent studies, we investigated whether SAH patients admitted directly to high-volume specialized centers fared better than patients transferred to these centers from community hospitals. Our first study was a retrospective analysis of SAH patients treated at a single high-volume neurovascular center.5 Our second study analyzed SAH patients from a nationwide sample.6 Here, we present the combined results of both studies. PATIENTS AND METHODS Our first study was a 3-year retrospective analysis of SAH patients treated at Cedars-Sinai Medical Center (CSMC), a comprehensive stroke center. CSMC is a 958-bed academic medical center with a 12-bed neuroscience intensive care unit (ICU). The neuroscience ICU is staffed with board-certified neurointensivists, and neurosurgical intervention is available 24 hours a day, 7 days a week, 365 days a year. Patient inclusion criteria were the following: age of 18 to 85 years, primary diagnosis of SAH (International Classification of Disease, Ninth Revision, Clinical Modification code 430), and monitoring with transcranial Doppler. Exclusion criteria were a history of trauma, vascular malformation, plans for palliative care implementation, or survival < 10 days after admission. The second study used data from the Nationwide Inpatient Sample NIS database for patients treated between 2002 and 2007. Inclusion criteria were age > 18 years, a primary diagnosis of SAH (International Classification of Disease, Ninth Revision, Clinical Modification code 430), and primary procedure of aneurysm clipping or coiling (International Classification of Disease, Ninth Revision, Clinical Modification code 39.51, 39.79, 39.72, or 39.52). Exclusion criteria included a history of trauma, vascular malformation, and lack of recorded admission source or discharge disposition. Patients who underwent both clipping and coiling procedures were also excluded. Patient age, sex, procedure (clipping or coiling), presence of ventriculostomy, and days to surgery were recorded in both studies. Outcomes of interest were length of stay (LOS), nonroutine discharge, mortality, vasospasm, and other complications. Non-routine discharge was defined as transfer to a long-term care facility, transfer to home hospice, or death. The national study also examined total cost of treatment. Statistical Analysis We used χ2 and t tests to evaluate differences in patient characteristics and outcomes (ie, mortality, LOS, complications) for the national cohort and hospital cohort for direct-admit and transferred patients separately. We used multivariate logistic regression to study mortality, nonroutine discharge, and complications in the national and single hospital cohorts separately. Adjusted odds ratio (OR), 95% confidence intervals (CIs), and corresponding P values were reported. US nationwide estimates were performed with SAS PROC SURVEY methodology. All analysis used SAS version 9.1 for Windows (SAS Institute Inc, Cary, North Carolina). RESULTS In the CSMC hospital study, a total of 107 patients were included (31 direct-admit and 76 transferred patients). Neurological status on admission was not significantly different between the directly admitted and transferred patients as evaluated by the Glasgow Coma Scale, nor was mortality. Directly admitted patients were less likely to experience vasospasm than transferred patients (32.2% vs 58.0%; P = .02). Additionally, direct-admit patients spent 3.9 fewer days in the ICU compared with transferred patients (t = −2.7, P = .009). Multivariate analysis demonstrated that vasospasm was associated with increased risk of additional complications (OR = 3.4; 95% CI = 1.0-12.0; P = .05) and death (OR = 6.6; 95% CI = 1.3-33.6; P = .02). In the national study, 47 114 patients were included (31 711 direct-admit and 15 403 transferred patients). There was no significant difference in disease severity in directly admitted and transferred patients at high-volume hospitals. Rates of complication, nonroutine discharge, and mortality were also similar in direct-admit and transferred patients at high-volume hospitals. In addition, at high-volume hospitals, transferred patients had a longer LOS (17.8 vs 16.9 days; P = .003) and incurred a higher total cost of treatment ($214 102 vs $196 730; P = .001). In the comparison of CSMC hospital and national data, 10 hospital patients were excluded because they did not undergo a clipping or coiling procedure. Demographics of hospital and national patients are summarized in Table 1. Data were similar between the national and single hospital patients with the exception of surgery type, incidence of coma (Table 1), and incidence of vasospasm (Table 2). Multivariate analysis also showed similar trends for the single hospital and national patients.TABLE 1: Characteristics of 47 211 Subarachnoid Hemorrhage Patients Treated With Coil or Clip Nationally and in a Single Hospital CohortaTABLE 2: Outcomes of 47 211 Subarachnoid Hemorrhage Patients Treated With Coil or Clip Nationally and in a Single Hospital CohortDISCUSSION One notable difference between the CSMC hospital and national data was the incidence of several complications. In the hospital study, coma was reported at a rate of 12% in direct-admit patients and 2.8% in transferred patients, but nationally, it was found in only 0.5% of direct-admit and 0.3% of transferred patients. A second disparity was the incidence of vasospasm (Table 2). Although both the hospital and national studies found that transferred patients experienced vasospasm with greater frequency than those directly admitted, the national rates for patients with vasospasm were far lower. We speculate that these disparities may be due to an underdocumentation of severity of disease in the Nationwide Inpatient Sample database. There has been conflicting evidence in the literature regarding the safety and effect of transfer on patient outcomes. Some studies have shown or suggested benefits to transferring critically ill patients,7,8 whereas others have reported that the risk of destabilization outweighs any benefit in treatment conferred by the higher standard of care at the receiving facility.9,10 In both our hospital and national studies, we found that transferred patients were no more likely to experience mortality than those directly admitted and, in the hospital study, were not at greater risk for aneurysm rebleeding. Initial transport to a neurovascular center is always preferable to transfer to a low-volume community hospital followed by a transfer to the specialized center. In the hospital study, transferred patients experienced higher rates of vasospasm (58% vs 32.3%; P = .02), a common but serious complication of SAH. Patients who experienced vasospasm spent 4.6 days longer in the ICU than those who did not (t = 3.4; P = .001), and vasospasm has been widely associated with mortality.11,12 In the CSMC hospital study, we found vasospasm to be a significant predictor of mortality (OR = 6.6; 95% CI = 1.3-33.6; P = .02). It is likely that this increased risk of vasospasm may be due to a delay in appropriate treatment. At high-volume specialized centers, the standard of care for SAH patients includes the placement of arterial lines to precisely monitor and control blood pressure and the administration of specialized medications (statins, calcium channel blockers, etc). At low-volume community hospitals, patients may not be treated with these interventions, thus delaying their standard-of-care treatment significantly until after their transfer. Another benefit of direct transport to a specialized center is a shorter time to surgical intervention. Shorter time to surgery has been significantly associated with lower mortality and complications in a number of studies.1,13 In our hospital study, time to treatment was significantly associated with ICU length of stay (t = 2.44; P = .02). The delay in advanced treatment management and surgical intervention may also help explain the increase in length of hospital course for directly admitted vs transferred patients on both the hospital and national levels (Table 3). The total cost of treatment for directly admitted patients was significantly lower than that for transferred patients in the national study ($214 102 vs $196 730; P = .001). The hospital study did not examine this variable; however, a regression analysis of the national study revealed that a 0.64 day increase in LOS would cost $2151 (Table 4).TABLE 3: Adjusted Odds Ratio of Mortality, Nonroutine Discharge, and Complications With Corresponding P Values for the National Cohort and the Hospital CohortaTABLE 4: Multivariate Regression Analysis for Length of Stay and Total ChargesThe benefits of regionalization for critical conditions such as SAH have been well demonstrated.3,4 Our findings are consistent with these previous studies.5,6 Patients directly transported to high-volume neurovascular centers were found to have lower rates of vasospasm and shorter, less costly hospital courses. Our results also argue for the benefits of transfer to a high-volume center even after initial admission to a community hospital. In our studies, transferred patients did not have higher overall mortality at either the hospital or national level. Although it is clear that direct transport to a high-volume hospital is the superior choice, a transfer benefits these critically ill SAH patients with a higher standard of care without destabilizing or negatively affecting them. CONCLUSION We hypothesized that direct admission to comprehensive stroke centers would result in better outcomes with fewer complications and shorter LOS. The trends observed in both our CSMC hospital and national studies present a strong argument for the regionalization of SAH care. Triage of presumed SAH patients should occur before the patient is transported to a low-volume community hospital. Our results also indicate that critically ill SAH patients can be transferred safely from community hospitals to comprehensive stroke centers. Because of the urgency of their specialized treatment needs, SAH patients should be transferred as soon as possible. Disclosures The authors have no personal financial or institutional interest in any of the drugs, materials, or devices described in this article. Acknowledgments We would like to thank Drs Chirag Patil, MD, and Patrick Lyden, MD, for their assistance with the previous manuscripts.