Prioritization of planetary health through health technology assessment: A scoping review

BackgroundPolicymakers lack structured, evidence-based processes and robust value assessments to guide planetary health investments. Health technology assessment (HTA)—a well-established framework for evidence-informed priority setting—has been proposed to address human and planetary health challenges under climate change. We aimed to assess whether existing evidence on adaptation can inform the prioritisation of planetary health interventions by examining their alignment with HTA criteria and decision-support tools.MethodsWe conducted a scoping review of adaptation interventions targeting climate-sensitive diarrheal disease or its determinants. Nine databases were searched from inception to May, 2025: BIOSIS Citation Index, CINAHL Complete, Econlit, Embase Classic+Embase, Global Health, GreenFILE, Medline ALL, Scopus and Web of Science Core Collection. Data was extracted on climate hazards, adaptation characteristics, outcomes, and HTA-relevant dimensions. Narrative synthesis and evidence gap maps were used to summarise patterns and identify gaps.FindingsIn total, 2924 studies were identified of which 88 studies describing 129 distinct adaptations were analysed. The findings highlight a disparate evidence base, with minimal alignment with HTA evaluative criteria or tools that facilitate prioritization within HTA, such as standardized criteria, economic evaluation and methods for addressing uncertainty.InterpretationAs climate change alters diarrheal disease patterns, governments must balance investments between current service delivery and future climate risks. Evidence on adaptation for diarrheal disease remains limited to inform such trade-offs from an HTA perspective. These findings highlight research needs for advancing adaptation evaluation and evolving HTA from a human to a planetary health focus.