Healthcare utilization and expenditures associated with appropriate and inappropriate implantable defibrillator shocks

Abstract

Background - In patients with implantable cardioverter-defibrillators, healthcare utilization (HCU) and expenditures related to shocks have not been quantified. Methods and Results - We performed a retrospective cohort study of patients with implantable cardioverter-defibrillators identified from commercial and Medicare supplemental claims databases linked to adjudicated shock events from remote monitoring data. A shock event was defined as ≥1 spontaneous shocks delivered by an implanted device. Shock-related HCU was ascertained from inpatient and outpatient claims within 7 days following a shock event. Shock events were adjudicated and classified as inappropriate or appropriate, and HCU and expenditures, stratified by shock type, were quantified. Of 10 266 linked patients, 963 (9.4%) patients (61.3±13.6 years; 81% male) had 1885 shock events (56% appropriate, 38% inappropriate, and 6% indeterminate). Of these events, 867 (46%) had shock-related HCU (14% inpatient and 32% outpatient). After shocks, inpatient cardiovascular procedures were common, including echocardiography (59%), electrophysiology study or ablation (34%), stress testing (16%), and lead revision (11%). Cardiac catheterization was common (71% and 51%), but percutaneous coronary intervention was low (6.5% and 5.0%) after appropriate and inappropriate shocks. Expenditures related to appropriate and inappropriate shocks were not significantly different. Conclusions - After implantable cardioverter-defibrillator shock, related HCU was common, with 1 in 3 shock events followed by outpatient HCU and 1 in 7 followed by hospitalization. Use of invasive cardiovascular procedures was substantial, even after inappropriate shocks, which comprised 38% of all shocks. Implantable cardioverter-defibrillator shocks seem to trigger a cascade of health care. Strategies to reduce shocks could result in cost savings.