Extended cost-effectiveness analysis in global health systems: a scoping review of geographic gaps and research trends

BACKGROUND: Extended Cost-Effectiveness Analysis (ECEA) extends conventional cost-effectiveness analysis by incorporating financial risk protection (FRP) and examining the distribution of health and economic outcomes across socioeconomic groups. This scoping review aimed to map the application of ECEA in health-sector studies, identify methodological patterns, and explore geographic and thematic research gaps. METHODS: A scoping review was conducted in accordance with PRISMA 2020 guidelines. Searches were performed on 29 October 2025 in PubMed, Scopus, Web of Science, ProQuest, and Google Scholar. Studies published between 2000 and 2025 that applied ECEA to evaluate health interventions were eligible for inclusion. Data were extracted on intervention characteristics, analytical approaches, equity measures, and FRP outcomes and were synthesized narratively. RESULTS: A total of 1,955 records were identified, of which 19 studies met the inclusion criteria. Most studies were conducted in low- and middle-income countries, particularly in Asia and Africa. The included studies primarily evaluated vaccination programs, taxation policies on harmful products, publicly financed health services, and maternal and child health interventions. Financial Risk Protection (FRP) outcomes were most commonly reported as reductions in out-of-pocket expenditures, catastrophic health expenditures averted, and poverty cases averted. Across studies, ECEA was predominantly used to assess the distribution of health and financial outcomes across socioeconomic groups, with outcomes commonly reported by income quintiles. CONCLUSION: ECEA applications remain limited and are predominantly concentrated in low- and middle-income countries, particularly within preventive and fiscal health interventions. The reviewed evidence suggests that ECEA provides a useful framework for assessing both health outcomes and financial risk protection across socioeconomic groups. Future research should expand ECEA applications to underrepresented settings and promote greater methodological standardization of equity and FRP measures.