Impact of age on sex-related differences in outcomes after aneurysmal subarachnoid hemorrhage

Background: Systematic investigations into the modifying effect of age on sex-related differences in postoperative outcomes after aSAH remain limited. This study aimed to clarify the role of age in the association between sex and poor outcomes. Methods: We retrospectively reviewed patients with aSAH who underwent surgical treatment and were consecutively admitted between January 2017 and December 2020 across 12 medical centers in four northern provinces of China. Multivariable logistic regression models were used to examine the association between sex and outcomes. Generalized additive models (GAMs) and segmented regression analyses were used to examine the nonlinear associations of sex and age with poor outcomes. Results: A total of 4865 patients were included in the analysis of sex and in-hospital outcomes, of whom 3979 completed follow-up and were included in the 2-year outcome analysis. Regarding 2-year outcomes, female patients exhibited significantly lower risks of poor outcomes (OR = 0.696, 95% CI: 0.564–0.859, P < 0.001) and mortality (OR = 0.558, 95% CI: 0.441–0.707, P < 0.001). Segmented logistic regression based on sex crossover points identified by the GAM at ages 42 and 78 revealed that within the 42–78-year age range, female patients had a significantly lower risk of poor outcomes compared with males (OR = 0.677, 95% CI: 0.543–0.844, P < 0.001). The GAM further indicated that the risk of poor outcomes in females began to increase notably after age 49. Using 49 years as a cutoff in segmented logistic regression, age prior to 49 was not significantly associated with 2-year poor outcomes in females (OR = 0.950, 95% CI: 0.883–1.021, P = 0.164), whereas age 49 and above was associated with a significant increase in risk (OR = 1.088, 95% CI: 1.071–1.105, P < 0.001). Conclusion: Age-related sex differences influence the risk of poor outcomes after aSAH, highlighting the importance of considering sex–age interactions in clinical decision-making.