Boston Scientific says it agrees with Medtronic’s comments on a newly published defibrillator analysis, which suggests the devices may be effective at preventing death from congestive heart failure only in men. A Boston Scientific spokesman points to two recent clinical studies that show implantable defibrillators are beneficial in women, perhaps even more so than in men in some cases.
Here’s Boston Scientific’s comment:
In the recently published MADIT-CRT trial, CRT-D (D is for defibrillator) therapy was associated with greater benefit in females (63%) than males (24%). There was no difference in mortality between men and women in either arm of the trial—CRT-D vs. ICD. This trial enrolled 1820 patients and 25% were women. To my knowledge this is the largest number of female enrollees in a medical device trial.
The second largest number of female enrollees were in the INTRINSIC RV Trial.
The INTRINSIC RV sub-analysis from Dr. Andrea Russo is in the September 2009 issue of the Journal of Cardiovascular Electrophysiology (20:9 973-978). It concludes the following: “In INTRINSIC RV, women receiving ICDs differed from men regarding baseline characteristics and drug therapy. After adjusting for baseline differences and medical therapy, there were no differences in heart failure hospitalization, survival, or ICD shock therapy during follow-up.”
The editorial which states that INTRINSIC RV has the largest number of absolute women to-date receiving an ICD in a clinical trial (which was true until MADIT-CRT published) is in the same issue (20:9 979-981). This editorial also states that “…this study is presently the largest investigation of the gender difference on arrhythmic risk and ICD effectiveness.”