Women receive cardioverter defibrillator less often

By Anthony J. Brown, MD

NEW YORK (Reuters Health) - Women who are hospitalized for heart failure are less likely than their male counterparts to receive an implantable cardioverter-defibrillator (ICD), a devise that monitors heart rhythms and delivers a shock if dangerous rhythms are detected, new research shows.

In a related study of Medicare patients, a similar gender gap was seen regarding use of ICDs to prevent sudden cardiac death.

As reported in the Journal of the American Medical Association, Dr. Adrian F. Hernandez, from the Duke Clinical Research Institute in Durham, North Carolina, and colleagues assessed ICD use among 13,034 patients who were discharged from the hospital after being treated for heart failure, a condition in which the heart muscle fails to pump enough blood out to the body.

When all eligible patients were considered, ICD use was only 28.2 percent for black women, 29.8 percent for white women, 33.4 percent for black men, and 43.6 percent for white men, statistically significant differences. On multivariate analysis, the adjusted odds of ICD use were 0.56, 0.62, and 0.73 for black women, white women, and black men, respectively, relative to white men.

In the second study, Dr. Lesley H. Curtis, a researcher at Duke who was also involved in the first study, and colleagues assessed ICD use for primary prevention (heart disease, but no prior cardiac arrest or tachycardia) of sudden cardiac death in over 135,000 Medicare patients and for secondary prevention (prior cardiac arrest or tachycardia) in over 99,000 patients.

ICD usage rates for primary prevention was 32.3 per 1000 men and 8.6 per 1000 women. On multivariate analysis, men were 3.15-times more likely to receive an ICD than were women.

For secondary prevention, ICD usage rates were 102.2 per 1000 men and 38.4 per 1000 women, which translates into a 2.44-fold increased odds of ICD use in men.

Among primary prevention patients alive 180 days after cohort entry, no survival benefit was seen at 1 year with ICD use. By contrast, among secondary prevention patients alive at 30 days after cohort entry, ICD use was tied to a 35 percent reduction in mortality at 1 year.

"Our study covers the time period since Medicare expanded coverage for ICDs," Curtis told Reuters Health. "We hoped that the gap between men and women would disappear with that expansion, but that was not the case. Men are still Two-to-three times more likely than women to get an ICD."

"We were surprised by the size of the gap between men and women. Even among survivors of cardiac arrest, men were 2-times more likely than women to receive an ICD. And studies have shown that these devices save lives," she added.

"We need to raise awareness of heart disease including sudden cardiac death or cardiac arrest in women and work to promote the use of the best care for all patients," Curtis emphasized. "Future studies should explore how physicians make decisions about which patients to recommend for ICDs and how patient preferences come into play. Currently, we are exploring how patterns of care are related to receipt of an ICD."

Journal of the American Medical Association, October 3, 2007.