RESUMO
Background: A need exists for safe, affordable, and effective antiviral treatments for less severe COVID-19 outpatients that can prevent infection progression, hospitalization, and death;shorten the time to clinical recovery;and reduce transmission. In our best knowledge, there are not, so far, costeffectiveness analysis on oral antiviral COVID-19 drugs in Spain. In our study we aim to evaluate cost-effectiveness of oral nirmatrelvir plus ritonavir in COVID-19 mild to moderate outpatients with at least one risk factor for disease progression in Spain. Method(s): A simulation model was constructed in R, to assess the clinical consequences and costs associated with COVID-19 in a hypothetical cohort of non-hospitalized patients older than 65 years with mild-to-moderate COVID and at least one risk factor for progression in Spain. The intervention assessed was nirmatrelvir plus ritonavir 300 mg plus 100mg every 12 hours up to 5 days. The comparator was symptomatic treatment with no antiviral drugs against SARSCoV- 2. The study was contextualized in the Spanish National Health System and the perspective of the service provider was adopted. Quality of life adjusted life years (QALYs) was used as a measure of effectiveness. Drug effectiveness was obtained from a literature review. As a cost measure, the retail price of the drugs was used. As a threshold willing to pay, the Spanish Gross National Product per capita was used. A discount of 3% per year was applied on future health effects. We used a decisional tree model. A univariate sensitivity analysis and probabilistic sensitivity analysis was performed. Result(s): We found that nirmatrelvir/ritonavir yielded an extra 620.89 QALYs compared to a baseline scenario without it, at an increase in cost of 89,630,442 with an Incremental cost-effectiveness ratio of 144,356.4 /QALY gained. One way sensitivity analysis and probabilistic sensitivity analysis using Monte-Carlo simulations were undertaken and showed that the probability of not being costeffective was 1 at the current price and willingness to pay threshold. To meet our willingness to pay threshold, nirmatrelvir plus ritonavir 5-days treatment price should be lowered down to 70 . Conclusion(s): According to our analysis nirmatrelvir/ritonavir is not costeffective in in the Spanish National Health System for outpatients older than 65 years with at least one risk factor for COVID progression. A drug price of 70 per treatment would meet our willingness to pay threshold.