OBJECTIVES: Indirect treatment comparisons (ITCs) are a technique used to compare the efficacy of two or more interventions in the absence of a head-to-head trial data. They are therefore an important tool used in health technology assessments (HTAs) to help determine the most cost-effective option and inform reimbursement decisions. In this analysis, we aimed to review trends in the use of different ITC methodologies, their impact on reimbursement success in Ireland, and common critiques noted by reviewers.

METHODS: A systemic review of all HTAs completed by the National Centre for Pharmacoeconomics (NCPE) between January 2018 and June 2023 was conducted. Data extraction included the date of review, therapy name and class, ITC usage and methodology, and reimbursement recommendations.

RESULTS: Between 2018 and 2023 a total of 129 HTAs were completed by NCPE, of which 71 (55%) included an ITC. The most common methodology used were network meta-analyses (n=36, 51%), followed by matched-adjusted ITCs (n=19, 27%), and naïve comparisons (n=12, 17%). The most common critique cited by the NCPE review group was unresolved heterogeneity in study designs included in the ITCs. Additionally, failure to adjust for all potential prognostic or effect modifying factors in matched-adjusted ITCs was a common critique and naïve comparisons presented alone were generally considered to be insufficiently robust for decision making. Regarding HTA outcomes, submissions using ITCs to establish comparative efficacy as opposed to head-to head trial data did not negatively impact recommendations, with 33.8% and 27.6% of submissions resulting in a positive recommendation, respectively.

CONCLUSIONS: ITCs are frequently used to support HTA submissions in Ireland. Submissions using ITCs to establish comparative efficacy do not appear to negatively impact recommendation results in comparison with head-to head trial data. Understanding the limitations and common critiques of ITCs can help to inform more successful application of these methods in the HTA submission process.