Among Medicare patients, men are about 2-3 times more likely than women to receive an implantable cardioverter-defibrillator for the prevention of sudden cardiac death, according to a study in the October 3 issue of JAMA.
Sudden cardiac death is a leading cause of death in the United States.
Overall, the risk of sudden cardiac death increases with age and is higher in men than in women, although the sex difference narrows and eventually disappears after age 85 years, according to background information in the article.
Research has shown the effectiveness of implantable cardioverter-defibrillators (ICDs) in preventing sudden cardiac death, and Medicare coverage of ICDs has expanded, but many eligible patients still do not receive them.
Lesley H. Curtis, Ph.D., of Duke University School of Medicine, Durham, N.C., and colleagues examined the differences between men and women in the receipt of ICDs for the primary and secondary prevention of sudden cardiac death. Data for the study came from a five percent national sample of files from the U.S. Centers for Medicare & Medicaid Services for the period 1991 through 2005. Patients in the study were age 65 years or older with Medicare fee-for-service coverage and diagnosed with a heart attack and either heart failure or cardiomyopathy (a disorder of the heart muscle), the primary prevention cohort: 136,421 patients; n = 65,917 men and 70,504 women; or with cardiac arrest or ventricular tachycardia (a cardiac arrhythmia), the secondary prevention cohort: 99,663 patients; n = 52,252 men and 47,411 women, from 1999 through 2005.
In the 2005 primary prevention group, 32.3 per 1,000 men and 8.6 per 1,000 women received ICD therapy within 1 year of entering the study. Men in this group were about 3.2 times more likely than women to receive an ICD. Among men and women alive at 180 days after group entry, the risk of death in the subsequent year was not significantly lower among those who received ICD therapy.
In the 2005 secondary prevention group, 102.2 per 1,000 men and 38.4 per 1,000 women received ICD therapy. After controlling for various factors, men in this group were about 2.4 times more likely than women to receive ICD therapy. Among men and women alive at 30 days after entry in this group, the risk of death in the subsequent year was 35 percent lower among patients who received ICD therapy.
“In this longitudinal analysis of Medicare beneficiaries at high risk for sudden cardiac death, we found significant sex differences in the use of ICD therapy from 1999 through 2005. Our findings in this cohort of elderly patients differ from an earlier study that suggested a narrowing of the gap between men and women, and they highlight the need for an improved understanding of sex differences in patterns of care,” the authors conclude.