Abstract
OBJECTIVES: To develop an empirically grounded, activity-based tariff framework for Hospital at Home (HaH) services using time-driven activity-based costing (TDABC) and micro-costing to support transparent and equitable reimbursement for acute elderly care delivered at home. DESIGN: Microcosting study embedded within a randomised controlled trial (RCT) comparing HaH with conventional hospital admission in Denmark. SETTING: Three municipalities in the Central Denmark Region in collaboration with emergency department physicians at a regional hospital. PARTICIPANTS: A consecutive subsample of 107 elderly acute patients enrolled in the RCT between June 2022 and February 2024. Resource use for HaH activities was measured prospectively using microcosting logs, time-motion observations and administrative records. MAIN OUTCOME MEASURES: Empirically derived tariffs per HaH visit (first and subsequent) calculated using an eight-step TDABC framework incorporating process mapping, resource identification, capacity cost rates and time equations. Sensitivity analyses tested robustness to variation in key cost drivers. RESULTS: The mean total tariff was €338.89 (95% CI €310.94 to €351.49) for first visits and €207.81 (95% CI €200.70 to €215.69) for subsequent visits, including treatment and transport components. Staff time was the principal cost driver, while equipment, overhead and travel reimbursement had smaller effects. The framework accommodates variation in staffing, geography and visit intensity and can be used to estimate total costs across diverse HaH pathways. CONCLUSIONS: A transparent and reproducible tariff-development framework for HaH services was established using TDABC and microcosting. The model aligns reimbursement with actual resource use and care complexity and provides a transferable template for economic evaluation and operational planning. TRIAL REGISTRATION NUMBER: NCT05360914.