To the Editor:

The recent publication by Reviriego-Rodrigo et al. (Reference Reviriego-Rodrigo, Cantero-Muñoz and Llinàs-Mallol1) describes the implementation of a patient and public involvement (PPI) monitoring protocol across the Spanish Health Technology Assessment Network (RedETS) (Reference Toledo-Chávarri, Gagnon and Álvarez-Pérez2). We welcome this initiative and its contribution to monitoring across agencies. However, complementary approaches are needed to fully characterize PPI in health technology assessment (HTA). The study relied on one-time self-reported information collected through online questionnaires from agency leads, HTA report coordinators, and participating patients in March 2025. This provides valuable insight into experiences and perceptions but does not directly assess how PPI is documented in published HTA reports. Self-reported data may also be influenced by recall and respondent interpretation. Systematic assessment of published HTA reports offers a complementary and reproducible perspective based on publicly available evidence, enabling broader sampling and more granular assessment of PPI practices (Reference Johnson, Uteh, Belilios and Pearson3;Reference Catalá-López, Ganuza and Colin4).

The finding that 20 of 49 HTA reports (41%) involved patients deserves closer interpretation (Reference Reviriego-Rodrigo, Cantero-Muñoz and Llinàs-Mallol1). The authors noted that PPI accounted for a small proportion of assessment time and often involved a single patient. Yet protocol review, validation of preliminary draft reports, consultation meetings, and qualitative research were grouped under the same PPI construct. These activities differ substantially in engagement and influence. PPI is not binary: the International Association for Public Participation (IAP2) distinguishes informing, consulting, involving, collaborating, and empowering (or coproducing) (5). Distinguishing these forms of participation is important to assess the depth and potential influence of PPI. Reviewing a protocol or draft report, for example, may confer less influence than jointly defining assessment questions, interpreting evidence, or developing recommendations.

Our meta-research protocol (Reference Catalá-López, Ganuza and Colin4) addresses this gap through systematic assessment of published HTA reports. We examine who participated, the level and nature of their involvement, the methods and stages through which it occurred, reported impacts, authorship, recognition, and compensation, and the transparency and completeness of reporting. This builds on the Guidance for Reporting Involvement of Patients and the Public (GRIPP2) statement (Reference Staniszewska, Brett and Simera6;Reference Catalá-López, Ganuza and Staniszewska7), which promotes transparent and comprehensive reporting of PPI in health and social care research. A recent EU report (Reference Lenz, Varkonyi and Dell’Aquila8) similarly recommends frameworks for evaluating patient-centered approaches and reporting tools informed by established standards such as GRIPP2. Such systematic reporting is feasible: Canada’s Drug Agency and Cochrane incorporate patient involvement into their assessment processes and use GRIPP2 to guide reporting in their outputs (9–Reference Henriques, Andrade and Silvério Serra12).

These approaches address complementary aspects of PPI. Triangulating information reported by interest holders with findings from published HTA reports can help distinguish three dimensions that should not be conflated: whether involvement occurred, how meaningful or influential it was, and how adequately it was reported. This matters because the presence of PPI does not, in itself, demonstrate meaningful participation, influence on decision making, or transparency. Strengthening the assessment and monitoring of PPI in HTA therefore requires moving beyond whether patients were involved to examining how they experienced the process, what difference their involvement made, and how clearly this was reported. Bringing these sources of evidence together could offer a more robust, transparent, and reproducible basis for evaluating PPI across HTA systems.