News & Commentary

Defibrillators Do Indeed Help Women


Implantable cardioverter defibrillators (ICDs) help women with heart failure as much as they help men, a study in Circulation: Heart Failure stated last month, again making the argument that gender-neutral guidelines for use of the devices should be followed.

They aren’t now, because in the randomized clinical trials that established the effectiveness of the devices years ago, only about 10% to 30% of the people who were enrolled were women.

Because ICDs have been proven to be effective, “ethical challenges make it unlikely that there will ever be a trial of primary prevention ICDs in women,” says the study, which was published online January 12. That sets up a Catch-22, because one reason women don’t get an ICD as often as men might arise from physician concern about the “paucity of evidence” that women would benefit.

Researchers with the Duke Clinical Research Institute mined Medicare data supplied by 264 hospitals enrolled in the Get With the Guidelines Heart Failure Registry. Looking at data from 2005 through 2012, they compared survival rates for patients with ICDs or who had been scheduled to receive one (430 women; 859 men) with patients with similar characteristics but no ICDs. The risk of death was more than 20% lower in both men and women with an ICD after three years. In addition, 40.2% of women with ICDs died, compared with 48.7% of women without the devices. For men, 42.9% with ICDs died, while 52.9% without them died.

Researchers touted how much effort went into matching patients in ICD and non-ICD groups in terms of age and severity of illness but concede that the study does not carry the same weight as a study that would randomly assign some of the patients to receive ICDs.

There’s a hard lesson in that, said lead author Emily Zeitler, MD, a research fellow at Duke: “When we don’t equitably enroll women or other important groups in trials, we can be left with less-clear answers on how to treat heart disease.”