National socioeconomic indicators are associated with outcomes after aneurysmal subarachnoid hemorrhage: a hierarchical mixed-effects analysis

Clinical article

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  • 1 Division of Neurosurgery, St. Michael's Hospital; Keenan Research Centre for Biomedical Science and the Li Ka Shing Knowledge Institute of St. Michael's Hospital; Department of Surgery, University of Toronto, Ontario, Canada; and
  • 2 Department of Government, Harvard University, Cambridge, Massachusetts
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Object

Although heterogeneity exists in patient outcomes following subarachnoid hemorrhage (SAH) across different centers and countries, it is unclear which factors contribute to such disparities. In this study, the authors performed a post hoc analysis of a large international database to evaluate the association between a country's socioeconomic indicators and patient outcome following aneurysmal SAH.

Methods

An analysis was performed on a database of 3552 patients enrolled in studies of tirilazad mesylate for aneurysmal SAH from 1991 to 1997, which included 162 neurosurgical centers in North and Central America, Australia, Europe, and Africa. Two primary outcomes were assessed at 3 months after SAH: mortality and Glasgow Outcome Scale (GOS) score. The association between these outcomes, nation-level socioeconomic indicators (percapita gross domestic product [GDP], population-to-neurosurgeon ratio, and health care funding model), and patientlevel covariates were assessed using a hierarchical mixed-effects logistic regression analysis.

Results

Multiple previously identified patient-level covariates were significantly associated with increased mortality and worse neurological outcome, including age, intraventricular hemorrhage, and initial neurological grade. Among national-level covariates, higher per-capita GDP (p < 0.05) was associated with both reduced mortality and improved neurological outcome. A higher population-to-neurosurgeon ratio (p < 0.01), as well as fewer neurosurgical centers per population (p < 0.001), was also associated with better neurological outcome (p < 0.01). Health care funding model was not a significant predictor of either primary outcome.

Conclusions

Higher per-capita gross GDP and population-to-neurosurgeon ratio were associated with improved outcome after aneurysmal SAH. The former result may speak to the availability of resources, while the latter may be a reflection of better outcomes with centralized care. Although patient clinical and radiographic phenotypes remain the primary predictors of outcome, this study shows that national socioeconomic disparities also explain heterogeneity in outcomes following SAH.

Abbreviations used in this paper:CI = confidence interval; GDP = gross domestic product; GOS = Glasgow Outcome Scale; HHH = hypertension, hypervolemia, and hemodilution; ICC = intraclass correlation coefficient; ICH = intracerebral hemorrhage; IVH = intraventricular hemorrhage; OR = odds ratio; SAH = subarachnoid hemorrhage; WFNS = World Federation of Neurological Societies.

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Contributor Notes

Address correspondence to: R. Loch Macdonald, M.D., Ph.D., St. Michael's Hospital, 30 Bond St., Toronto, ON M5B 1W8, Canada. email: macdonaldlo@smh.ca.

Please include this information when citing this paper: published online August 15, 2014; DOI: 10.3171/2014.7.JNS132141.

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