Cardiac resynchronization therapy in women versus men: Observational comparative effectiveness study from the national cardiovascular data registry

Background.Women have been under-represented in trials of cardiac resynchronization therapy-defibrillators (CRT-D). Previous studies suggest that women benefit from CRT-D at shorter QRS duration than men and that there may be no benefit of CRT-D in patients without left bundle branch block (LBBB) regardless of patient sex. Methods and Results.We compared sex-specific death risk in 75 079 patients with New York Heart Association class III or IV heart failure, reduced left ventricular ejection fraction, and prolonged QRS duration (.120 ms) receiving either CRT-D or implantable cardioverter defibrillator in subgroups according to QRS morphology and 10-ms increments in QRS duration. We applied propensity score weighting to control for differences between treatments. Among patients with LBBB, women receiving CRT-D had a lower relative death risk than those receiving an implantable cardioverterdefibrillator (absolute difference, 11%; hazard ratio=0.74 [95% confidence interval, 0.68.0.81]). In men, the lower mortality with CRT-D versus implantable cardioverter defibrillator was less pronounced (absolute difference, 9%; hazard ratio=0.84 [0.79.0.89]; sex-device interaction P=0.025). In those without LBBB, the mortality difference was modest and did not differ between women and men (absolute difference, 3%; hazard ratio=0.88 [0.79.0.97] in women and absolute difference, 2%; hazard ratio=0.95 [0.91.0.998] in men; interaction P=0.17). In subgroups according to QRS duration, CRT-D was associated with better survival in both sexes with LBBB and QRS .130 ms, whereas there was no clear relation between QRS duration and survival in patients without LBBB regardless of patient sex. Conclusions.In a large real-world population CRT-D was associated with a lower mortality risk in both sexes with LBBB, although more pronounced among women. Only among those with LBBB, both sexes had better survival with longer QRS duration. The mortality differences in patients without LBBB were attenuated in both sexes.