The Effect of Weight Loss on Clinical Outcomes in Patients Implanted With a Cardiac Resynchronization Therapy Device-A MADIT-CRT Substudy

Background: There are no data regarding the effect of weight loss on clinical outcomes in patients undergoing cardiac resynchronization therapy. This study was designed to evaluate the effect of weight loss on clinical outcomes in patients implanted with a cardiac resynchronization therapy with defibrillator (CRT-D). Methods and Results: The risk of heart failure (HF) or death, and of death alone, was compared between patients with and without weight loss of >= 2 kg or more at 1 year in the CRT-D arm of the Multicenter Automatic Defibrillator Implantation Trial Cardiac Resynchronization Therapy (MADIT-CRT). Weight loss was observed in 170 of 994 patients (17%) implanted with a CRT-D. Multivariate analysis showed a significant increase in the risk of HF or death among patients with weight loss compared with those without weight loss (hazard ratio [RR] 1.82, 95% confidence interval [CI] 1.26-2.63; P =.001). Weight loss was associated with a 79% increase in the risk of all-cause mortality (HR 1.79, 95% CI 1.16-3.34; P = .01). When analyzed in a continuous fashion, each kg of weight loss was associated with a 4% increase in the risk of HF or death (P = .03). In left bundle branch block (LBBB) patients with a CRT-D, weight loss was associated with an especially high risk of HF or death (HR 2.23, 95% CI 1.36-3.65; P = .002) and of death alone (HR 2.33, 95% CI 1.07-5.06; P = .03; interaction P = .26). Conclusions: In patients with mild symptoms of HF receiving CRT-D, weight loss observed at 1 year is associated with adverse clinical outcomes, especially in those with a LBBB electrocardiographic pattern.