OBJECTIVES: In 2019, cost-effectiveness analyses by the health technology assessment (HTA) agency officially commenced in Japan and patients and the public have participated in the meetings. Japan's HTA system is still in its infancy and its scope of implementation is limited. This review provides up-to-date information from earlier reviews and identifies the objective/value of patient and public involvement (PPI), the forms of implementation, and future measures needed in Japan.

METHODS: A series of review of the systematic review (SR) [1], articles covered by SR [2], and new articles after SR [3] was conducted. Articles listed in MEDLINE and Embase until December 2023 on PPI in HTA were searched with terms like "patient participation/involvement," "community participation," "public involvement," and "health technology assessment." The scope of the articles for [3] were restricted to those from Australia, Canada, and the UK. The information obtained from [1] to [3] was categorized into objectives/vale of PPI, methods of implementation, and resources required. For details of implementation, I extracted publicly available information from HTA agencies ans added Japanese information to examine these differences.

RESULTS: The SR search identified 6 reviews [1] out of 2006 candidates and 54 references in those reviews, from which 7 articles were selected [2], and 7 articles from the 2832 candidates [3] . The review identified reflections on the process by patients and the public. No significant differences were in the opprtunities for participation between Australia, Canada, the UK, and Japan, but neither information was on how patient and public input was collected and reflected in the reports, nor the objectives of the PPI describes in the reviews.

CONCLUSIONS: Japan's HTA presents similar opprtunities for PPI as in other countires, but the objectives and impact of PPI are not clear. Future PPI should be conducted with patients and public in an easy-to-understand way.