Clinical effectiveness of cardiac resynchronization and implantable cardioverter-defibrillator therapy in men and women with heart failure: findings from IMPROVE HF.

BACKGROUND: Many clinical trials have demonstrated a benefit for cardiac resynchronization (CRT) and implantable cardioverter-defibrillator (ICD) therapies in patients with heart failure and reduced ejection fraction, yet questions have been raised with regard to the benefit of ICDs for women. The purpose of this study was to determine the clinical effectiveness of CRT and ICD therapy as a function of sex in outpatients with heart failure and reduced ejection fraction (≤35%).

METHODS AND RESULTS: Data from the Registry to Improve the Use of Evidence-Based Heart Failure Therapies in the Outpatient Setting (IMPROVE HF) were analyzed by device status and sex among guideline-eligible patients for vital status (alive/dead) at 24 months. Multivariate generalized estimating equation analyses were conducted adjusting for baseline patient and practice characteristics. In the ICD/CRT-defibrillator (CRT-D) eligible cohort (n=7748), there were 5485 (71%) men and 2261 (29%) women. In the CRT-pacemaker (CRT-P)/CRT-D eligible cohort (n=1188), there were 824 (69%) men and 364 (31%) women. The clinical benefit associated with ICD/CRT-D therapy was similar in both men and women (men adjusted odds ratio, 0.71; 95% confidence interval, 0.57-0.87; P=0.0012; and women adjusted odds ratio, 0.65; 95% confidence interval, 0.49-0.85; P=0.0019). For CRT-P/CRT-D, the associated benefits showed no significant heterogeneity (men adjusted odds ratio, 0.59; 95% confidence interval, 0.33-1.06; P=0.0793; and women adjusted odds ratio, 0.44; 95% confidence interval, 0.22-0.90; P=0.0243). The device-by-sex interactions were not significant (P=0.4441 for CRT-P/CRT-D and P=0.5966 for ICD/CRT-D).

CONCLUSIONS: The use of guideline-directed CRT and ICD therapy was associated with substantially reduced 24-month mortality in eligible men and women with heart failure and reduced ejection fraction. Device therapies should be offered to all eligible patients with heart failure, without modification based on sex.