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Executive Summary

Hospital Characteristics and Mortality in Aneurysmal Subarachnoid Hemorrhage

Sheehan, Tiffany O.; Davis, Nicolle W.; Peach, Brian C.; Ansell, Margaret; Cimiotti, Jeannie P.; Guo, Yi; Lynch Kelly, Debra; Yoon, Saunjoo L.; Horgas, Ann L.

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Journal of Neuroscience Nursing: February 2021 - Volume 53 - Issue 1 - p 2-4
doi: 10.1097/JNN.0000000000000549
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Aneurysmal subarachnoid hemorrhage (aSAH) is a neurological emergency associated with high mortality rates. Population-based studies have reported mortality rates ranging from 8% to 67%.1,2 For the past 2 decades, several hospital certification programs have been developed, recognizing the various specialties and hospital resources needed to support quality stroke care and improved outcomes in aSAH. Hospital and patient characteristics have been reported as 2 major constructs critical to understanding mortality outcomes in aSAH. Patient-related predictors of mortality including older age, neurological disease severity, comorbid conditions, rebleeding of the aneurysm, global cerebral edema, intracerebral hemorrhage, vasospasm, delayed cerebral infarction, hyperglycemia, fever, pneumonia, and sepsis are extensively reported in the litearture.2 Less is understood about the hospital characteristics associated with improved patient outcomes, specifically mortality. As hospitals align resources and develop programs at the organizational level to optimize aSAH care, it is important to develop high-quality, population-based studies that evaluate the successful translation of evidence-based medicine into clinical practice. This executive review summarizes the existing literature on the hospital characteristics associated with mortality in aSAH patients and identifies gaps in the literature specific to the role of advanced practice registered nurse (APRN) and aSAH outcomes.


We conducted a systematic search of PubMed, Web of Science, and EBSCO's Cumulative Index to Nursing and Allied Health Literature, Health Business Full Text, and Public Administration Abstracts databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.3 We included articles published between 2010 and 2018. Searches were constructed using terms related to the concepts of hemorrhagic stroke, hospital resources, hospital environmental factors, and mortality outcomes. The search strategy identified 1482 articles, of which 214 were duplicates, leaving 1268 articles to be screened for inclusion criteria. A total of 1260 articles were excluded, leaving 8 articles included in this review. Hospital characteristics reported in the literature and associated with mortality included the following: annual case volume (n = 5), certified stroke center admission (n = 1), and staffing models (n = 2).


Case Volume

The studies that examined hospital annual aSAH case volume were inconsistent in their findings. Of the studies that found a significant decrease in in-hospital mortality for patients treated at high-volume stroke centers,4–7 there was variability in how case volume and disease severity were measured or whether it was included at all.5 One nationwide study revealed a significant association between case volume and in-hospital mortality; for every 5 aSAH cases annually, there was a 21% decrease in odds of mortality (odds ratio [OR], 0.79; 95% confidence interval [CI], 0.67–0.92; r = −0.222, P < .001).5 Patients treated at high-volume centers (≥20 cases per year) had an 18% decrease in the odds of death (OR, 0.82; 95% CI, 0.72–0.95; P < .01) when compared with low-volume centers (<20 cases per year).7 Another study indicated that patients treated at low-volume centers (<12 cases per year) were found to have an increase in the odds of 30-day mortality (OR, 1.5; P < .0001) when compared with those treated at high-volume centers (>88 cases).4 Finally, older patients treated at low-volume hospitals had a 52% increase in the odds of death (OR, 1.52; 95% CI, 1.05–.2.19; P = .10).8 Conversely, in a regional study, there was no statistically significant difference in in-hospital mortality (17.9% vs 18%, P = 1.000) between patients admitted to a high-volume unit (>50 cases) versus a low-volume unit (<18 cases), which shared neurocritical care, neurosurgery, and endovascular practitioners.6

Certified Stroke Center Admission

Medicare beneficiaries (>65 years old) discharged from a certified primary stroke center had a 34% decrease in the odds of 30-day mortality (OR, 0.66; 95% CI, 0.58–0.76; P = .001) when compared with nonstroke centers.9

Staffing Model

Two studies examined mortality after implementing various staffing models. One retrospective study evaluated the impact of a neurointensive care unit without a neurointensivist versus a neurointensive care unit with a 24/7 neurointensivist on in-hospital, 3-month, and 12-month mortality at a primary stroke center. The availability of a neurointensivist was associated with a significant decrease in the percentage of in-hospital mortality (31.7% vs 18.5%, P = .006), 3-month mortality (31.7% vs 20.1%, P = .018), and 12-month mortality (33.7% vs 20.8%, P = .01).10 A single-center study compared the effect of a nocturnist APRN coverage model in the neurocritical intensive care unit compared with overnight neurocritical care coverage with general critical care physicians and neurology residents on in-hospital mortality (n = 58). The addition of the APRN showed a 10% reduction in mortality; however, the difference was not statistically significant (24% vs 15.7%, P = .54).11


This review shows gaps in the literature including the variability in how hospital characteristics, disease severity, and mortality were measured, thus lacking the necessary evidence to determine which hospital characteristics are associated with mortality among aSAH patients. Hospital characteristics found to have a significant association with mortality included case volume, admission to a certified primary stroke center versus a noncertified stroke center, and the availability of a neurointensivist.

Results regarding the impact of annual case volume have been inconsistent. Of the studies that found a significant decrease in in-hospital mortality for those patients treated at high-volume stroke centers,4,5,7,8 there was variability in how case volume and disease severity were measured. Hospital experience, specialized services, staffing, nursing expertise, and an organized interdisciplinary team may explain the mortality benefit observed at high-volume centers. Additional research is needed to explore these factors that may influence the association between case volume and mortality outcomes.

Only 1 study evaluated the impact certification programs have on aSAH mortality.9 However, this study was conducted before the implementation of comprehensive stroke centers and, therefore, only reported primary stroke centers versus noncertified centers. In addition, this study excluded young aSAH by only including Medicare beneficiaries older than 65 years. Nonetheless, this study supports the notion that stroke centers provide superior quality care as compared with those centers not certified. Additional research is needed to explore comprehensive stroke centers' impact on mortality outcomes.

Only 2 studies evaluated mortality after implementing various staffing models; the availability of a physician neurointensivist reported significant associations with decreased mortality.10,11 In this review, only 1 study examined the role of an APRN as a hospital characteristic associated with aSAH mortality. Although the study showed a 10% reduction in mortality with a nocturnist APRN coverage model, the difference was not statistically significant.11 This might be explained by the small sample size and the lack of adjustment for severity of illness. Both studies took place at a single center limiting its generalizability to other centers, and neither study adjusted for disease severity of illness, a confounding factor recognized in the literature.12

Studies have shown the impact of APRN care on neuroscience patient outcomes, highlighting that APRN care promotes patient satisfaction, reduced costs, and reduced length of stay.13–15 To date, the literature on the outcomes of APRNs has focused on comparing APRNs with other providers including medical residents, fellows, and attending.14 Complex diseases such as aSAH require complex coordination to provide optimal care.16 APRNs are an integral part of the interdisciplinary team and comprehensive stroke center certification programs. As part of an interdisciplinary team, there is a joint decision-making process based on each practitioner's education and ability.17 The interactions between each discipline of the interdisciplinary team contribute to the quality of patient care and subsequent patient outcomes. It is important to understand the unique contributions of each discipline within the team to identify their collective impact on outcomes. Very little is understood about the specific contributions APRNs caring for aSAH have on mortality outcomes. Future research is needed to first identify the unique contributions of APRNs and then develop APRN-sensitive metrics to aid in the evaluation of their unique influence on mortality outcomes of aSAH patients. This evaluation may be used to optimize APRN care delivery and support their utilization in the care of the aSAH patient population.


There is a lack of rigorous evidence on hospital characteristics and aSAH mortality. The absence of standardized measures of hospital characteristics, disease severity, and mortality limits our understanding of how to improve aSAH outcomes. Standardized measures of hospital characteristics, disease severity, and mortality should be explored in future research. Furthermore, to improve aSAH outcomes, a more comprehensive understanding of hospital characteristics is needed, including how the availability of APRNs might be associated with the care outcomes of patients with aSAH. Future research should also explore the development of standardized APRN-sensitive measures to evaluate the contributions of APRN care and management on aSAH mortality outcomes. Studies that examine hospital characteristics should include advanced practice providers, such as APRNs. It is only when we include data on all care providers can we truly determine the care outcomes of patients with aSAH.


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