ICD therapy for primary prevention may not benefit women
MedWire News: Implantable cardioverter defibrillator (ICD) therapy for primary prevention of sudden cardiac death (SCD) does not reduce mortality in women, a US meta-analysis has revealed, highlighting the need for gender-specific data in this, and other areas, of cardiovascular medicine.
A pooled analysis of 934 women enrolled in five primary prevention trials in patients with systolic heart failure found that there was no significant difference in all-cause mortality with ICD therapy compared with medical therapy (hazard ratio [HR]=1.01).
By contrast, there was a significant reduction in all-cause mortality with ICD therapy versus medical therapy among the 3810 men in these trials (HR=0.78, p<0.001).
Study authors Christian Machado and colleagues from Providence Hospital Heart Institute and Medical Center in Southfield, Michigan, write in the Archives of Internal Medicine: “Most clinical trials have been heavily weighted toward men; therefore, generalization of the results to women remains questionable.”
The researchers explain that multiple clinical trials demonstrating the benefit of ICD therapy in patients with HF with reduced left ventricular ejection fraction for the primary prevention of SCD have led to broad acceptance of the approach and significantly increased rates of ICD implantation in this population. However, they say, most patients studied have been male.
Machado and team point out that still only a minority of patients implanted with ICDs are female (around 30%), probably at least in part due to the paucity of data in women.
Nevertheless, Rita Redberg (University of California, San Francisco, USA) says their findings show that “ICDs are being implanted in hundreds of thousands of women without substantial evidence of benefit, apparently based on the assumption that, to paraphrase the old saying, ‘What’s good for the gander is good for the goose.’ ”
Writing in a related editorial, Redberg explains that current US Food and Drug Agency (FDA) guidelines indicate that gender-specific data should be reviewed with every drug application, but a recent study showed that around one-third of drug applications in 1998 did not fulfill such requirements, and that while inclusion of women and gender-specific analysis had improved in some therapeutic areas by 2003, this was not true for cardiovascular disease.
The review of gender-specific data should also become mandatory prior to medical insurance national coverage decisions, according to Redberg.
Agreeing with Machado and co-authors that further studies are needed, Redberg describes some promising developments, including that US Congress is currently considering the Heart for Women Act, seeking to ensure that women with heart disease, stroke, and other cardiovascular diseases are properly diagnosed and effectively treated.
“In addition, the FDA Center for Devices and Radiological Health held workshops in 2008 to discuss solutions to the problem of under-representation of women in clinical trials of cardiovascular products,” she adds.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a part of Springer Science+Business Media. © Current Medicine Group Ltd; 2009
By Caroline Price