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Factors to Consider When Analyzing Sex Differences in Myocardial Infarction

  • Atsuyuki Watanabe
    Correspondence
    Requests for reprints should be addressed to Atsuyuki Watanabe, MD, Department of Respiratory Medicine, Tsukuba Gakuen Hospital, 2573-1, Kamiyokoba, Tsukuba, Ibaraki 305-0854.
    Affiliations
    Department of Respiratory Medicine, Tsukuba Gakuen Hospital, Tsukuba, Japan
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      To the Editor:
      Asleh et al demonstrated a large excess risk of recurrent myocardial infarction for females in their recently published article, entitled “Sex Differences in Outcomes After Myocardial Infarction in the Community” in the January 2021 issue of The American Journal of Medicine.
      • Asleh R
      • Manemann SM
      • Weston SA
      • et al.
      Sex differences in outcomes after myocardial infarction in the community.
      Utilizing geographical and social characteristics, their extended follow-up provided remarkable evidence. In addition, they maintained statistical power using propensity score weighting, indicating the patient's sex as a risk factor for MI recurrence. Their findings will reinforce existing evidence and help bridge the therapeutic gap between males and females.
      However, although they sophisticatedly analyzed the results with the inverse probability weighting method to homogenize the two groups, the included variables seemed to be inadequate. For instance, Liu et al previously demonstrated higher in-hospital mortality of ST-elevation myocardial infarction for females than males. However, the difference was insignificant after the two groups were adjusted with reperfusion and revascularization therapies, except for the youngest subgroup.
      • Liu J
      • Elbadawi A
      • Elgendy IY
      • et al.
      Age-stratified sex disparities in care and outcomes in patients with ST-elevation myocardial infarction.
      In contrast, in the present study, the included variables to estimate the propensity scores were age, cardiovascular risk factors, comorbid conditions, and myocardial infarction characteristics. Because revascularization is essential in myocardial infarction treatment, and because there were significant differences in revascularization therapies between the two groups at baseline, an additional analysis with the new propensity score, taking revascularization into account, should be performed. I strongly believe this perspective will promote better understanding of pathophysiological differences of myocardial infarction between the sexes and possibly save more lives in the future.

      References

        • Asleh R
        • Manemann SM
        • Weston SA
        • et al.
        Sex differences in outcomes after myocardial infarction in the community.
        Am J Med. 2021; 134: 114-121
        • Liu J
        • Elbadawi A
        • Elgendy IY
        • et al.
        Age-stratified sex disparities in care and outcomes in patients with ST-elevation myocardial infarction.
        Am J Med. 2020; 133: 1293-1301.e1