Introduction: This study describes and quantifies the univariate effect of age and gender on 3-month functional outcome after aneurysmal subarachnoid hemorrhage (aSAH) using the largest repository of aSAH patients to date.
Methods: Individual patient data on age and gender (n=10950) were extracted from 7 randomized clinical trials and 3 prospective tertiary hospital datasets contained in the Subarachnoid Hemorrhage International Trialists (SAHIT) repository. The strength of prognostic association was analyzed with binary and proportional odds logistic regression. Consistency of prognostic effect across datasets was examined with forest plots. Age was analyzed as a continuous predictor with spline functions, and the effect calculated as the odds ratio over the difference between the 75th and 25th percentiles. Adjusted analysis accounted for the effect of clinical severity.
Results: Increasing age was strongly associated with poorer outcome (OR: 1.86; CI: 1.76 – 1.96). The effect of age was found to be continuous but nonlinear (p=0.001), with a change point occurring at the age group of 60 – 69 years. A significant gender effect was found (OR: 1.17; CI: 1.08 – 1.27) which was attenuated in adjusted analysis (OR: 1.03; CI: 0.91 – 1.15). There was no significant gender/age interaction (p= 0.4701); and the effect of age or gender did not differ statistically between RCT cohorts and prospective hospital cohorts (interaction: age, p= 0.1795; gender p= 0.4677).
Conclusions: This study confirms that outcome after aSAH is dependent on age but not on gender. A sharp decline in prognosis is likely to occur after the age of 69 years.
Patient Care: This research will help practitioners gain a better understanding of the prognostic relevance of two constituent patient characteristics.
Learning Objectives: By the conclusion of this section, participants should be able to:
1.)Have a better understanding of the effect of age and gender on SAH outcomes.
2.)Identify patients potentially at risk of poorer short term functional outcomes. 3.) Have conversations around possible factors that could be contributory to our findings