Gender and survival after sudden cardiac arrest: A systematic review and meta-analysis.

Background: Conflicting results exist regarding the impact of gender on early survival after sudden cardiac arrest (SCA). We aimed to assess the association between female gender and early SCA survival.
Methods: We searched Embase, MEDLINE, EBM Reviews, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews (between 1948 and January 2014) for studies evaluating the association between gender and survival after SCA. Two independent reviewers selected studies of any design or language. Pooled odds-ratios (OR) and 95% confidence intervals (CIs) were estimated using a random-effects model. Additional sensitivity analyses and meta-regression were carried out to explore heterogeneity.
Results: Thirteen studies were included involving 409,323 patients. Women were more likely to present with SCA at home, less likely to have witnessed SCA, had a lower frequency of initial shockable rhythm but were more likely to receive bystander CPR. After adjustment for these differences, women were more likely to survive at hospital discharge (OR 1.1, 95% CI 1.03-1.20, p=0.006, I(2)=61%). This association persisted in multiple sensitivity analyses.
Conclusion: This meta-analysis of observational studies demonstrates that women have increased odds of survival after SCA. Further studies are needed to address mechanisms explaining this discrepancy.
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