Introduction: Differences between centers in patient outcome after subarachnoid hemorrhage from ruptured intracranial aneurysms (SAH) could be of relevance for design of multicenter studies, particularly randomized clinical trials (RCT), and standardization of management practices for improved quality of care for all patients. This study was aimed at investigating whether differences in outcome exist between centers enrolling patients into RCTs in SAH, and if so, quantifying such center effect.
Methods: We analyzed 6036 patients who were enrolled into 3 multicenter randomized clinical trials (IHAST, IMASH and Tirilazad) in SAH, using random effects logistic regression models to estimate the between-center differences in unfavorable outcome at 3 month on the Glasgow outcome score. We compared centers at the lower end of the outcome distribution (2.5th percentile) to those at the higher end of the outcome distribution (97.5th percentile), while accounting for differences in patient baseline characteristics. The analysis was performed for the entire cohort, and stratified by region.
Results: The 6036 patients were enrolled at 176 centers from North America, Europe and Oceania, with 1603 (26.8%) experiencing unfavorable outcome at 3-month. We found a 3.8-fold difference in odds of unfavorable outcome between centers at the lower end of the outcome distribution compared with centers at the higher end of the outcome distribution, after adjusting for differences in patient characteristics. The difference between centers was higher in Europe (6.28-fold), lower in Oceania (3.00) and non-existent in North America (1.00).
Conclusions: The outcomes of patients who are enrolled into multicenter clinical trials in SAH differ considerably between centers and regions. The reasons and implications of these findings should be studied, as such might lead to improvement in some aspects of trial design and management practices.
Patient Care: By contributing to a better understanding of between-center differences in patient outcome after SAH, the research might motivate further inquiry for the reasons for such between-center differences, which could identify those areas where management practices could be potentially improved.
Learning Objectives: 1. Have a better understanding of between-center variability in outcome after aneurysmal subarachnoid hemorrhage
2. Discuss the likely reasons for the study findings
3. Discuss the implications of our findings for prospective multicenter studies in SAH, and patient care