Supplementary Material for: Digital health–enabled monitoring strategies for AF detection after ESUS: A cost-effectiveness analysis of implantable loop recorders, wearable devices, and usual care

Abstract
Background: Embolic stroke of undetermined source (ESUS) is frequently attributable to atrial fibrillation (AF), yet remains undetected when episodes are brief or asymptomatic. Digital health–enabled cardiac monitoring offers novel pathways for secondary prevention. Implantable loop recorders (ILRs) provide continuous long-term rhythm surveillance, while wearable ECG devices offer greater accessibility but with uncertain diagnostic yield and economic value. We evaluated the cost-effectiveness of ILR versus wearable AF monitoring and usual care in ESUS.
Methods: A cohort-based Markov model simulated 1,000 ESUS patients (mean age 65 years) over a 10-year horizon from the German statutory health insurance perspective. Clinical inputs included AF detection rates (ILR: 15–25%; wearables: 5–10%), risk reduction in ischemic stroke with oral anticoagulation, and mortality/disability utilities. Costs (2024 €, 3% discount) captured device acquisition, implantation, follow-up, stroke care, and anticoagulation. Outcomes included incremental cost-effectiveness ratio (ICER) and incremental net monetary benefit (NMB) at willingness-to-pay thresholds of €20,000, €30,000, and €50,000/QALY. Deterministic and probabilistic sensitivity analyses, including expected value of perfect information (EVPI), were performed.
Results: ILR yielded 0.23 additional QALYs compared with wearables at an incremental cost of €2,160, resulting in a base-case ICER of €9,391/QALY. In a high-risk subgroup, the ICER decreased to €5,520/QALY. Probabilistic analysis demonstrated >90% probability of cost-effectiveness at €30,000/QALY, with moderate EVPI. These findings align with meta-analytic evidence (RR 3.88 for AF detection; RR 0.75 for stroke reduction) and indicate that prolonged monitoring (≥12 months) maximises yield.
Conclusion: Digital health–enabled ILR monitoring is likely cost-effective for AF detection after ESUS, particularly in high-risk patients. Wearables may serve as an adjunct but deliver lower value. Results support targeted ILR implementation in post-ESUS care pathways and integration into digital health–driven guideline and reimbursement frameworks.