OBJECTIVES: Exacerbations are considered one of the main drivers of costs of Chronic Obstructive Pulmonary Disease (COPD). In moderate to severe COPD patients with a history of exacerbations, the addition of an inhaled corticosteroid (ICS) to a long acting β2 agonist (LABA) has been associated with a decreased rate of exacerbations versus treatment with LABA alone. This study aims to estimate the healthcare costs that the addition of the ICS Fluticasone Furoate (FF) to the LABA vilanterol (VI) could avoid versus LABA monotherapy in Spanish patients due to the reduction of the rate of exacerbations. METHODS: The number of moderate to severe COPD patients >40 years old with a history of exacerbation potentially treated with FF+VI was estimated from Spanish prevalence data. 1-year Monte-Carlo simulations (one simulation per patient) were developed to simulate the number of moderate and severe exacerbations and the healthcare costs avoided with FF+VI versus VI from the National Health System (NHS) perspective. Monte-Carlo simulation was chosen as it allows simulating the effect of changes in different parameters obtained from clinical studies to describe real-life distributions. Parameters used in the simulations were the yearly rate of moderate-severe exacerbations with FF+VI and VI obtained from pooled-analysis of two head-to-head clinical trials (NCT01009463 and NCT01017952) and the costs of moderate and severe exacerbations obtained from an observational study in real-life Spanish setting. RESULTS: