Economic evaluation synthesis: time for a methodological update to support equitable decision-making

The increasing reliance on valid and reliable evidence from research studies for decision-making has led to tremendous improvements in health policy and practice interventions.1 The systematic synthesis of research studies, a more modern evolution of this movement, has further improved decision-making, particularly in the realm of health intervention effectiveness. This entails putting research studies through the rigorous evidence synthesis process, including the clear and a priori identification of a precise clinical or public health research question, the selection of studies that match all aspects of this question, the appraisal of the methodological rigor of those studies, and the extraction and pooling of relevant data from these studies.2 The field of systematic reviews of economic evidence as an approach for assessing the efficiency of health interventions has grown significantly since its inception. Building on the work of other scholars in this field,3-6 the JBI Economic Review Methodology (JERM) group published a foundational paper7 and JBI Reviewers' Manual chapter8 that provided guidance on the aims and methods for conducting systematic reviews of economic evidence. Since the publication of this work, numerous examples of substantial methodological advances in the field of economic evaluation synthesis9-15 and significant interest in the application of such methods are noted, as demonstrated by the 2015 JBI paper7 being cited over 200 times (Google Scholar) to date. These ongoing developments prompted the re-formation of the JERM group in 2024. Although the methodologies for producing primary research evidence of efficiency in public health and health care are now well developed and consist of a set of economic evaluation approaches,16 this type of evidence often is still not systematically evaluated via evidence synthesis or systematic review methodology.17 Some scholars even suggest that synthesizing evidence from these types of studies is, in most cases, rather futile, due to the inherently complex nature of health economic evaluations that can make them context-specific.18 One way that this critique manifests is in whether or not meta-analysis of primary health economic evaluations can or should be done given the inherently varied impact of context, including political and sociocultural factors, on the valuation of costs for a given health technology or intervention. In addition to heterogeneity of effects inherent in all quantitative research, health economic evaluations contain heterogeneity in costs and resource use in both time (eg, from one year to the next) and space (eg, from one country, region, healthcare system, or provider to the next), which compounds the challenges of meta-analyzing this type of evidence. In this editorial, the authors propose that despite these challenges, it is critical to subject primary health economic evaluations, like all other primary research study designs, through the rigorous evidence synthesis process. This is particularly critical if the goal is to achieve equity in decision-making regarding efficiency. The need to consider the efficiency of health and health care technologies or interventions (eg, their cost effectiveness, cost utility, or cost benefit), and whether they make a difference in reducing health inequities, have long been identified as additional important elements in evidence-based decision-making.19,20 Given that the reduction of health inequities requires the allocation of greater amounts of resources, which in most cases means a more equitable distribution of existing resources, to focus on improving the health of those groups who need the most help, it is evident that efficiency and equity are intrinsically related. Systematic reviews increase equity in efficiency by ensuring that the chosen perspective of the analysis is made evident in relation to the more equitable gold standard of the societal perspective; a structured opportunity is created for broader inclusion/demographics of participants/population; the outcomes of interest are selected a priori; the health technologies or interventions are clearly identified in relation to other more relevant, necessary, or equitable alternatives; the relative quality of the chosen studies is made manifest; all available relevant studies are considered (including those that show a negative or null effect); and the role of chance variation is accounted for. Simply put, the synthesis of health economic evaluations helps address the same perennial challenge that is faced in the ever-growing health effectiveness literature: the cherry-picking problem, whereby decisions are made at the policy table with either full knowledge or willful ignorance of the presence of both systematic and random errors in the available evidence. The authors propose that the synthesis of evidence from primary health economic evaluations is paramount for achieving equity in population health, and that evidence synthesis of such studies must always be a critical component of the process of decision-making in health care practice and public health policy. Economic systematic reviews must be conducted despite the ongoing methodological developments in this approach and the multiple considerations that can be viewed as obstacles to economic evaluation synthesis relative to other more established review methodologies. The re-formation of the JERM group will help advance this aim by offering updated and ongoing expert guidance on the planning, conduct, and reporting of systematic reviews of economic evidence. Acknowledgements The current members of the JBI Economic Review Methods (JERM) group, who have all made valuable contributions to the work of the group: Yuri Jadotte, Denny John, Dru Riddle, Judith Gomersall, Norma Bulamu, Suzy Lockwood, Sonia Hines, Ghislaine van Mastrigt, and Luke Vale.