Atrial fibrillation is associated with worse outcomes in women than in men

Emdin CA, Wong CX, Hsiao AJ, et al.
BMJ 2016;352:h7013

Background

Studies suggest that cardiovascular risk factors weight differently for females and males. For example:

• smoking and diabetes are associated with higher proportional risks of coronary heart disease in women compared with men [1,2]
• diabetes is associated with a greater relative risk of stroke in women [3]

Atrial fibrillation is associated with an increased risk of stroke and death [4,5], but it is not clear whether gender differences exist for this risk factor. Some studies have suggested that atrial fibrillation is more strongly associated with the risk of stroke [6] and death [7] in women compared with men, but other studies have not confirmed these results [8].  
This meta-analysis of cohort studies was conducted to assess the relationship between atrial fibrillation and cardiovascular disease and death in women and men and to determine whether atrial fibrillation is a stronger risk factor for cardiovascular disease and death in women compared with men.

Main results

• 30 studies with 4,371,714 participants were included in the meta-analysis
• Atrial fibrillation was associated with

• a higher risk of all-cause mortality in women (RR for women compared with men: 1.12, 95% CI: 1.07 - 1.17).
• a significantly stronger risk of
  • stroke (RR: 1.99, 95% CI: 1.46 - 2.71)
  • cardiovascular mortality (RR: 1.93, 95% CI: 1.44 - 2.60)
  • cardiac events (RR: 1.55, 95% CI: 1.15 - 2.08)
  • heart failure (RR: 1.16, 95% CI: 1.07 - 1.27)

        for women compared with men

• Looking at events per 1000 patient years, corresponding absolute risk increases in outcomes

associated with AF in women compared with men were for:

• all-cause mortality (RR: 1.8, 95% CI: 1.1 - 2.6)
• cardiovascular mortality (RR: 4.3, 95% CI: 1.9 - 7.5)
• stroke (RR: 3.1, 95% CI: 1.1 - 6.1)
• cardiac events (RR 0.6, 95% CI: 0.03 - 1.3)
• heart failure (RR: 6.1 , 95% CI: 2.1 - 12.7)

Conclusion

Atrial fibrillation is associated with a stronger relative risk of all-cause mortality, cardiovascular mortality, stroke, ischemic heart disease, and heart failure in women compared with men. Further research is necessary to explore any causality underlying these observations. These data support the development of a specific stroke risk score for women. It might be appropriate for clinicians to treat women with atrial fibrillation more intensively.

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References

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