Adults with heart failure who received implantable cardioverter defibrillators (ICDs) for primary prevention had a significant survival advantage compared with those who did not receive ICDs, according to a propensity score-matched analysis of Medicare patients.
After three years of follow-up, the mortality rates were 40.2 percent among women who received an ICD and 48.7 percent among women who did not receive an ICD. Meanwhile, the mortality rates were 43.3 percent among men who received an ICD and 50.9 percent among men who did not receive an ICD.
The researchers said there were no significant sex-based interactions for the survival benefits associated with ICDs.
Lead researcher Emily P. Zeitler, MD, of the Duke Clinical Research Institute in Durham, North Carolina, and colleagues published their results online in Circulation: Heart Failure. The Agency for Healthcare Research and Quality funded the study.
“The associated survival benefit appeared early post hospitalization but was not sensitive to the exclusion of patients who died within a month of discharge, and this benefit was present throughout available follow-up,” the researchers wrote. These data support current guideline recommendations for the implantation of a primary prevention ICD in eligible women and men with [heart failure] and reduced [left ventricular ejection fraction].”
The researchers mentioned that only 10 percent to 30 percent of patients enrolled in clinical trials assessing ICDs were women. They added that fewer women use primary prevention ICDs even though guidelines recommend them for men and women with heart failure. Thus, they were interested in evaluating the devices in women.
In this analysis, the researchers obtained data from Get With The Guidelines for Heart Failure (GWTG-HF) and the Centers for Medicare and Medicaid Services (CMS). GWTG-HF, which began in 2000, is a voluntary hospital-based quality improvement program. The researchers linked the GWTG-HF and CMS claims data for admissions from Jan. 1, 2005 through Dec. 31, 2012 using a validated method.
The analysis included 3,788 women in the GWTG-HF registry who had heart failure and reduced left ventricular ejection fraction, who were at least 65 and whose primary insurance was Medicare. Of those women, 430 had an ICD implanted or prescribed during the index hospitalization. The researchers matched those patients with ones who did not receive an ICD.
They also evaluated 5,273 men who fit the same criteria. Of those men, 863 had an ICD implanted or prescribed.
Women who received an ICD were more likely to be younger and be admitted to a larger teaching hospital compared with women who did not receive an ICD. The mean age was 76 for women receiving an ICD and 80 for women not receiving an ICD.
The researchers said the overall risk of mortality was significantly lower among women with an ICD and that the difference began early after implantation. They added that a similar survival advantage was found in men who received an ICD compared with men who did not receive an ICD.
After one year, the mortality rates were 17.3 percent among women who received an ICD and 23.6 percent among women who did not receive an ICD. Meanwhile, the mortality rates were 19.4 percent among men who received an ICD and 25.0 percent among men who did not receive an ICD.
The study had a few limitations, according to the researchers, including that patients were not randomized. They mentioned it was possible that patients may have not had an ICD implanted or prescribed because they could have been too sick to undergo the procedure. In addition, the study was limited to Medicare patients who were admitted to a hospital that voluntarily participated in the GWTG-HF registry, so the results may not be generalizable to other patient populations.