Implantable defibrillator results may vary for women, as do many heart factors

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Just because implantable defibrillators have been found to prevent sudden cardiac death in heart failure patients in general doesn’t mean they reduce mortality in female patients specifically. In fact, they don’t appear to do so at all.

Such is the conclusion of a study published Monday in Archives of Internal Medicine. Researchers at Providence Hospital Heart Institute and Medical Center in Michigan analyzed the results of five studies and found the devices yielded little real impact on overall deaths in women with heart failure.

That doesn’t necessarily mean female patients should not use defibrillators. As cardiologist Dr. Bruce Wilkoff of Cleveland Clinic notes in a Bloomberg News story: “I don’t think it means we shouldn’t treat women. Maybe they weren’t being treated adequately for other difficulties.”

The blog CardioBrief, also cited in Monday’s post on the nation’s abominable showing when it comes to heart-disease risk factors, continues in this vein, stressing that the findings don’t condemn defibrillators.

It quotes Dr. Richard Fogoros as saying: ‘ICDs prevent sudden arrhythmic death equally well in men and women. So it is not appropriate to conclude that ICDs do not “work” in women, but rather, that the relative risk of arrhythmic may be different in women. It is entirely possible, and even likely, that appropriately selecting which women with heart failure ought to receive ICDs (i.e., determining which individuals have a relatively high risk of sudden arrhythmic death) would be a different process than for men.’

Ultimately, the research -- and the comments -- reiterate the fact that we should be careful with our assumptions. Broadly extrapolating results of studies done in men to women, perhaps especially when it comes to heart disease, is risky.

As the authors of the report write (here’s the abstract): ‘Most clinical trials have been heavily weighted toward men; therefore, generalization of the results to women remains questionable. The best answer to this problem would be to perform a clinical trial that specifically targets women with heart failure to test the hypothesis of whether ICD implantation reduces their overall mortality rate.’

Here’s more on heart disease from Medline Plus -- plus heart disease in women.

-- Tami Dennis