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Frailty and Efficacy of Primary Prevention ICDs Among HF Patients
Quick Takes
- Primary prevention ICD therapy is associated with a lower risk of all-cause mortality among HFrEF patients who have baseline low frailty burden.
- Among older participants aged ≥65 years, those with low frailty burden had a significant reduction in their mortality risk with ICD therapy for primary prevention.
- High frailty burden was associated with a higher risk of all-cause hospitalization, CV death, and sudden cardiac death.
Study Questions:
Can the baseline frailty status of patients with heart failure (HF) be used to predict who will benefit the most from placement of an implantable cardioverter-defibrillator (ICD) for primary prevention?
Methods:
Patients with HF and reduced ejection fraction (HFrEF; n = 1,673) from SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial), a multicenter, randomized, controlled trial conducted from 1997–2001, were grouped into low frailty (median frailty index [FI], 0.30) or high frailty (median FI, 0.54) burden groups at baseline according to the Rockwood Frailty Index to include variables regarding comorbidities, functional status, quality of life, and biomarkers. The primary outcome was all-cause mortality, and the secondary outcomes were cardiovascular (CV) mortality, sudden cardiac death (SCD), and all-cause readmission. Multivariable Cox proportional hazards models were used to evaluate the adjusted association of the FI to the outcomes adjusting for age, sex, race, HF etiology, and New York Heart Association class (II vs. III). The relationship of age (<65 years or ≥65 years) was analyzed to assess the treatment effect of ICD therapy on CV and all-cause mortality.
Results:
Baseline higher frailty burden was associated with a 45% higher risk of all-cause mortality (hazard ratio [HR], 1.45; 95% confidence interval [CI], 1.20-1.76; p < 0.001) versus patients with lower frailty burden. Patients with high frailty burden at baseline had higher CV risk factors, HF symptoms, and worse functional status. Overall, the ICD therapy had a significant improvement in the low frailty groups for all-cause mortality (p = 0.001), CV mortality (p = 0.001), and SCD (p < 0.001). The number of appropriate shocks observed on follow-up ICD interrogations was modestly higher among those with high versus low frailty burden (3.0% vs. 2.5% of ICD interrogation episodes with appropriate ICD shocks captured, p = 0.041); however, there was no significant difference in ventricular tachycardia/ventricular fibrillation (VT/VF) detected or VT/VF treated with the ICD between frailty groups. There was no significant difference in CV deaths or non-CV deaths.
Among patients with HFrEF ICD therapy, a lower risk of all-cause mortality was associated with those having a low frailty burden (HR, 0.56; 95% CI, 0.40-0.78) versus a high frailty burden (HR, 0.86; 95% CI, 0.68-1.09). In age-stratified analysis, there was a significant association between frailty burden and efficacy of ICD therapy. Older patients (>65 years) with a low frailty burden had a significantly lower risk of all-cause mortality with ICD therapy versus older patients with higher frailty burden (p = 0.001 vs. p = 0.42). Among younger patients (aged <65 years), ICD therapy efficacy was similar across both low or high frailty burden groups (p = 0.14 vs. p = 0.02).
Conclusions:
Among patients with HFrEF, the baseline frailty burden was associated with the treatment effect of ICD placement for primary prevention. A significant reduction in mortality risk was associated in patients with a lower frailty burden, but not among those with a higher frailty burden.
Perspective:
This study brings insight into how frailty burden, rather than physiological age, may influence how ICDs are allocated based on their efficacy or ability to produce the most benefit for the patient. The authors found an association between frailty status and the risk of all-cause mortality in HFrEF patients who have received an ICD for primary prevention. A patient with baseline lower frailty burden is more likely to benefit from ICD therapy regardless of age, but there was no benefit in patients aged ≥65 years with a high frailty burden. Since there were no significant differences in VT/VF episodes treated by the ICD placed across high and low frailty groups, the higher mortality seen in the high frailty group may have represented clinical worsening due to other cardiac or noncardiac comorbidities. Since frailty can affect the quality of life and ultimately patient outcomes, clinicians may consider counseling patients with a baseline high frailty burden, especially those aged ≥65 years, about the benefits of physical therapy, rehabilitation, or other treatments targeting comorbidities to improve their functional status and frailty burden shown to reduce the risk of all-cause mortality and SCD.
Clinical Topics: Arrhythmias and Clinical EP, Cardiovascular Care Team, Implantable Devices, SCD/Ventricular Arrhythmias, Prevention
Keywords: Defibrillators, Implantable, Frailty, Heart Failure, Reduced Ejection Fraction
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