Effect of country or continent of treatment on outcome after aneurysmal subarachnoid hemorrhage

Abstract

Prognostic factors for outcome after aneurysmal subarachnoid hemorrhage (SAH) include the clinical and pathological characteristics of the patient and hemorrhage as well as some aspects of treatment. Because treatment can vary between countries and continents, the authors used a large database of patients with SAH to determine the effect of the geographic location of treatment on outcome. Data obtained in 3567 patients who were entered into randomized trials of tirilazad between 1991 and 1997 were analyzed. Patients underwent treatment in 162 neurosurgical centers in 21 countries in North America, Europe, Africa, and Australia. The dependent variable was clinical outcome assessed 3 months after SAH with the Glasgow Outcome Scale, which was analyzed as a 5-point variable and dichotomized into favorable (good recovery or moderate disability) and unfavorable (severe disability, vegetative state, or death) outcomes. The effect of country or continent of treatment on outcome was assessed using univariate and multivariate logistic regression and proportional odds modeling before and after adjusting for numerous other factors significantly associated with outcome. The authors constructed several multivariate analysis models and demonstrated that for almost every model, country was not a significant predictor of outcome (p>0.05). There was variation in outcome between countries, but this was mostly due to differences in other admission characteristics that influence outcome such as age, clinical grade, and subarachnoid clot thickness. Because the number of patients entered from some countries was small, countries were grouped, and the data were analyzed by continent. This grouping gave more stable estimates and created an appropriate model for both logistic and proportional odds models and again showed that continent had no significant effect on outcome. Despite the variations in treatment that undoubtedly exist between countries and continents, the location of treatment had minimal effect on outcome. Outcome was influenced mostly by clinical characteristics on admission such as neurological grade, patient age, and amount of SAH.