CRT upgrade improves frailty status in patients with HFrEF and RV pacing—a post hoc analysis of the BUDAPEST-CRT trial

Frailty and heart failure (HF) both have become increasingly prevalent and each adversely affects prognosis. Data regarding the potential frailty-modifying effect of cardiac resynchronization therapy (CRT) upgrade remain scarce. This study aimed to evaluate the impact of frailty on clinical outcomes in the Budapest-CRT Upgrade trial population. Patients with heart failure and reduced ejection fraction (HFrEF), an implanted pacemaker or implantable cardioverter-defibrillator (ICD) and ≥ 20% right ventricular pacing burden were randomized to CRT-D upgrade (n = 215) or ICD alone (n = 145). Our primary endpoint was all-cause mortality, HF-hospitalization and or < 15% reduction of left ventricular end-systolic volume at 12 months. Frailty was assessed using a 31-item frailty index (FI) based on the Rockwood method, and patients were dichotomized according to the median FI. Among 360 patients, the mean baseline FI was 0.39 ± 0.10, with follow-up FI available in 282 patients at 12 months. CRT-D upgrade significantly decreased the risk of the primary endpoint regardless of baseline FI compared to ICD alone (interaction p = 0.17). CRT-D upgrade led to a 0.03-point greater reduction in the mean FI change compared to the ICD arm (mean FI difference at 12-month - 0.03; 95% CI - 0.04 to - 0.01; p = 0.005). In this highly comorbid cohort, frailty was common but it did not diminish the clinical benefit of CRT-D upgrade. CRT-D upgrade decreased the risk of the primary endpoint regardless of baseline frailty status and led to a significant decrease in mean FI change compared to ICD alone.