Predictors of death without prior appropriate therapy in ICD recipients: the comorbidities, frailty and functional status (COMFFORT study).

Objective: Most patients who have an implantable cardioverter-defibrillator (ICD) implant do not receive life-prolonging therapy from it. Little research has been undertaken to determine which patients benefit the least from ICD therapy. As patients age and accumulate comorbidities, the risk of death increases and the benefit of ICDs diminishes. We sought to evaluate the impact of comorbidity, frailty, functional status on death with no prior appropriate ICD therapy.

Methods: A prospective, multicentre, observational study involving 12 English hospitals was undertaken. Patients were eligible for inclusion for the study if they were scheduled to have a de novo, upgrade to or replacement of a transvenous or subcutaneous ICD or cardiac resynchronisation therapy device and defibrillator (CRT-D). Baseline characteristics were collected. Participants were asked to complete a frailty assessment (Fried score) and a functional status questionnaire (EuroQol 5-Dimension 5-Level (EQ-5D-5L)). The Charlson Comorbidity Index was calculated. Patients were prospectively followed up for 2.5 years. The primary outcome was death with no prior appropriate therapy.

Results: In total, 675 patients were enrolled, mean age 65.7 (IQR 65-75) years. A total of 63 patients (9.5%) died during follow-up, 58 without receiving appropriate ICD therapy. Frailty was present in 86/675 (12.7%) and severe comorbidity in 69/675 (10.2%). Multivariate predictors of death with no appropriate therapy were identified and a risk score comprising frailty, comorbidity, increasing age, estimated glomerular filtration rate and EQ-5D-5L was developed.

Conclusion: Comorbidities, frailty and the EQ-5D-5L score are powerful, independent predictors of death with no prior appropriate therapy in ICD/CRT-D recipients.