OBJECTIVES: This analysis aimed to evaluate the cost-effectiveness of nirmatrelvir/ritonavir in the treatment of adults with COVID-19 not requiring supplemental oxygen with high-risk factors for developing severe COVID-19 compared to no treatment from the Spanish National Health System perspective.

METHODS: A cost-effectiveness model was developed using a decision tree for the first year (acute phase) followed by a two-state Markov model (alive or dead) with annual cycles for a lifetime horizon. For each comparator, 1,000 high-risk patients with symptomatic COVID-19 entered the decision tree (after the intervention) segmented into two arms: inpatients and outpatients. For inpatients, the level of care (general ward; Intensive Care Unit (ICU) with or without mechanical ventilation) and hospital mortality associated with COVID-19 were considered. For outpatients, the duration of symptoms was considered, and the absence of mortality was assumed. Survivors of the acute phase entered in the Markov model. Nirmatrelvir/ritonavir efficacy in reducing hospitalisations, deaths and symptom days was extracted from the EPIC-HR trial. Quality of life (utility and disutility associated with hospitalisations and disease symptoms) and costs (€, 2024) were considered. For all patients, nirmatrelvir/ritonavir cost, and resource use associated with diagnosis, prescribing and initial follow-up were contemplated. Additionally, hospitalisation and post-discharge follow-up costs for the acute phase were considered for inpatients. Lifetime average healthcare costs per person were considered until death. The assumptions and parameters were derived from nationally published data, where possible, and validated by experts. A probabilistic sensitivity analysis (PSA) was performed.

RESULTS: Nirmatrelvir/ritonavir resulted a dominant option vs. no treatment, with a decreased cost per patient (-€169.69) and an increased quality-adjusted life-years (QALYs; +0.05). Nirmatrelvir/ritonavir was cost-effective or dominant in 100.0% of PSA simulations (32.3% and 67.7%, respectively) using a €25,000/QALY threshold.

CONCLUSIONS: Nirmatrelvir/ritonavir is a dominant option compared to no treatment in high-risk patients with symptomatic COVID-19 in Spain.