Cost-effectiveness of Preventive Transarterial Embolization for Splenic Artery Aneurysm Below the Guideline-Recommended Size Threshold: A Japanese Claims-Based Study.

Purpose: Preventive transarterial embolization (TAE) for splenic artery aneurysm (SAA) is recommended in high-risk cases owing to the high mortality after rupture. This study evaluated the cost-effectiveness of preventive TAE for SAAs smaller than guideline-recommended threshold of 30 mm.

Materials and methods: A Markov model with six states (well without treatment, well after treatment, TAE for aneurysm growth, recanalization, rupture, and death) was developed to compare preventive TAE with the watch-and-wait strategy using 1-year cycles over a lifetime. Model parameters were derived from prior studies and a national administrative claims database in Japan. The base case was a 60-year-old female with SAA measuring 20 mm. The incremental cost-effectiveness ratio (ICER) was evaluated against Japan's willingness-to-pay threshold of 5 million yen per quality-adjusted life year (QALY). Deterministic and probabilistic sensitivity analyses incorporated scenarios varying multiple parameters.

Results: Analysis of 2,870 patients undergoing preventive TAE for SAAs from the database revealed an ICER of 3,522,204 yen/QALY (22,724 USD/QALY) in the base case, below the threshold. The ICER exceeded the threshold at 71.4 years in females and 65.9 in males. Quality-of-Life (QOL) improvement by treatment (12 to 24 months and longer), time to QOL difference resolution, age at discovery and costs of preventive TAE were the key ICER influencers. Without QOL improvement, preventive TAE was not cost-effective.

Conclusion: Preventive TAE for SAA may be cost-effective, but only when treatment leads to improvements in QOL. These findings highlight the importance of patient selection and can guide cost-conscious clinical decision-making and reimbursement policy.