The proposed scoping review will follow the methodology outlined by the JBI (formerly Joanna Briggs Institute) for conducting scoping reviews (16, 17) and will adhere to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for scoping reviews (PRISMA-ScR (18)). Recent updates of PRISMA 2020 (19), specifically the scoping review modifications as detailed in the scoping review chapter of the JBI manual on evidence synthesis (20), will also be taken into consideration.
The primary purpose of this protocol is to predefine the review’s objectives, review questions, eligibility criteria, methodologies, and reporting guidelines, to ensure transparency. The protocol functions as a plan for the scoping review and is designed to mitigate potential reporting biases. Any deviations from the established protocol during the review will be clearly addressed and explained within the complete scoping review (20). The protocol was registered in the Open Science Framework (https://osf.io/3jmsa).
A collaborative effort was initiated, bringing together a team of global experts specializing in guideline methodology and planetary health, with the purpose of contributing to this scoping review. To enhance our application of the JBI scoping review guidance and PRISMA-ScR, and to refine our screening, study selection and data extraction, pilot testing phases were undertaken at each step. The pilot phase aimed to achieve the following objectives: (a) evaluate and enhance the methods outlined in the protocol; (b) establish and train a team of reviewers (c) establish essential group procedures; (d) create and enhance the required tools; (e) fine-tune the process and content of data extraction; and (f) ascertain the scope of our work. During the pilot, we employed an adapted approach, and after its conclusion, we further refined the methods for the proposed scoping review. This section outlines the fundamental methods employed in the proposed scoping review.
2.1 Review Question:
Our goal will be to address the following review questions:
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What are dimensions of planetary health that have been considered in health guidelines and HTAs?
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How have guideline development methodologies suggested that health guidelines or HTAs consider the environment, climate change, or planetary health?
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What are the methods that health guidelines and HTAs have used to incorporate evidence and assess the certainty of evidence of planetary health outcomes?
2.2 Eligibility Criteria
2.2.1 Concept:
According to The Lancet definition, planetary health is defined as, “The achievement of the highest attainable standard of health, wellbeing, and equity worldwide through judicious attention to the human systems—political, economic, and social—that shape the future of humanity and the Earth's natural systems that define the safe environmental limits within which humanity can flourish. Put simply, planetary health is the health of human civilisation and the state of the natural systems on which it depends” (8). The intricate mechanisms underpinning the linkage between human health and the surrounding natural systems remain multifaceted and occasionally elusive. This discourse shifts its focal point primarily towards outcomes that transcend human-centric considerations. The concept of focus here will predominantly be on non-human centric outcomes because past HTAs and health guidelines have historically concentrated on direct human outcomes. Thus, the imperative emerges to place substantial emphasis on the well-being of animals and the equilibrium of natural systems as measured by the planetary boundaries concept, with the recognition that the ultimate preservation of human health is fundamentally interconnected between all (21–23).
2.2.2 Context:
We will include any human health guidelines or HTAs covering the breadth of clinical, health system and public health topics, that also address planetary health outcomes (including a focus on animal health and natural systems). We will include the most recent version of the report if there are multiple versions. We will include methodological papers or handbooks that provide insight into how to address planetary health in the guideline or HTA process. We will include guidelines and HTAs published in any language, employing translation tools when studies are included beyond the languages of our team. We will not restrict eligibility based on geography or the level of government/region a guideline is focused on.
2.2.3 Types of sources:
This scoping review will focus on health guidelines and HTAs that address planetary health outcomes including those that have a focus on animal health, natural systems, and the environment.
2.2.4 Exclusion criteria
In our exclusion criteria, we will exclude any studies or reports not directly related to planetary health. This includes reports or studies unrelated to health guidelines or health technology assessments. Additionally, we will exclude LCA modeling studies that do not form a part of a guideline or HTA. Furthermore, if an abstract does not explicitly reference planetary health, one health, ecosystem health, or climate change, or related concepts we will exclude it from consideration for full-text screening. Concepts related to sustainability that are not relevant to environmental or planetary health, such as sustainable financing, will also be excluded. Lastly, studies focusing solely on the impacts of climate change or the environment on health (i.e., not the opposing direction health interventions on the environment) will not be included in our review.
2.3 Search Strategy:
The search strategy was developed in consultation with a health sciences librarian at McMaster University. The search will identify guidelines and HTAs that have addressed planetary health outcomes or considerations. We will complete a primary search of the literature using the following databases: Ovid MEDLINE, EMBASE, CINAHL, Global Health, Health Systems Evidence, Greenfile, and Environmental Issues. We will complement this search with the GIN international guideline library and registry of guidelines in development (24), BIGG international database of GRADE guidelines (25), Epistemonikos GRADE guidelines repository (26), GRADEpro GDT Database of GRADE EtD’s and Guidelines (27), MAGICapp (28), National Institute for Health and Care Excellence (NICE) website (29), and the World Health Organization website (30). We will also complement this with a search for online content on Google incognito mode with similar search terms to identify any unpublished documents of relevance. In addition, the search will be further complemented by utilizing another ongoingscoping review of handbooks on guideline development, that identified 120 international guideline development handbooks by diverse organizations, to search for references to planetary health in these handbooks (31). The search strategy for different databases has been provided in the Supplementary File.
2.4 Evidence Selection:
A web-based software platform Covidence (32) will be used to automatically remove duplicates and to screen the retrieved articles. The screening of citations will be carried out in two phases, both of which will go through pilot testing. Two review authors will independently screen the title and abstract of the citations based on the prespecified inclusion and exclusion criteria. A simple screening algorithm as outlined in Appendix 2 will be employed. Any discrepancies will be resolved through a third reviewer.
Two reviewers will individually assess the full texts of the identified eligible documents based on the predetermined criteria for eligibility. Any conflicts will be resolved by a third reviewer. The reasons for exclusion will be documented in the full-text screening phase. A simple screening algorithm as outlined in Appendix 3 will be employed. All pertinent complete guideline texts and HTA reports will be gathered and shared using an online folder. This folder will encompass associated documents and supplementary materials. The comprehensive details of the search results and the study inclusion process will be thoroughly documented in the final scoping review. This information is visually presented using a Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) flow diagram (19) in Fig. 1: PRISMA flow diagram depicting search results before data extraction, and will continue to be updated in the final scoping review once the data extraction process begins. Additional details can be found in the PRISMA-P checklist [see Additional file 1].
2.5 Data Extraction
Using a pilot-tested and standardized extraction form, a team of experienced reviewers will be responsible for extracting data from the guidelines and HTA reports incorporated in this scoping review. One reviewer will perform preliminary data extraction, and this will be verified by a second reviewer. Any disagreements will be resolved through discussion or involving another reviewer. The team will convene for regular meetings to address any potential concerns that might arise. These meetings will also serve the purpose of maintaining consistency and providing training to all reviewers. The primary investigator of the project will then review and refine the extracted data for each guideline and/or HTA. The following data will be extracted: document title; first author’s names; publication year; language; document type (peer review publication, guideline handbook, report, grey literature, other); whether the document is a guideline or HTA; the topic/discipline (respirology, gastroenterology, nutrition, anesthesia, other); document purpose/study objective; developing/sponsoring organization; country in which the study/guideline/HTA report was conducted (United States, UK, Canada, Australia, Germany, other); definition of planetary health or related concept provided; types of planetary health experts engaged (engineer, one health/veterinary, economist, modelling expert, geologist/earth scientist, other); study methods; suggested methods to assess planetary health (LCA, other modelling approach, use of existing databases, direct measurement, expert input on impact, other); whether the study uses secondary data on planetary health outcomes; description for use of LCA; description for assessing quality of life cycle; population/intended audience; interventions; category (human health, animal health/one health, natural systems, environment, other); applicable planetary health boundaries (climate change, change in biosphere integrity, stratospheric ozone depletion, ocean acidification, biogeochemical flows, land-system change, freshwater use, atmospheric aerosol loading, introduction of novel entities); consideration of social justice/global equity; phase of intervention in life cycle related to planetary health addressed (goods production, goods transport, patient/staff travel, diagnostic tests, facility requirements, infection prevention and control (IPAC) requirements, disposal impacts, other); measure of planetary health impact (carbon dioxide emissions, methane emissions, other greenhouse gas emission, nitrogen/phosphorous inputs, energy input, water use, waste production, monetary equivalents of impact, other); impact on biodiversity/land use and one health/animal welfare mentioned; funding (not transparent, public funding, private funding, both public and private funding, other), conflict of interest (reported or not reported).
2.6 Data Analysis and Presentation
Data analysis will involve a combination of content analysis using both deductive and inductive approaches, along with the utilization of descriptive statistics. Part of the data collected, specifically the yes/no items, will be converted into quantitative form, and basic descriptive statistical methods will be employed to examine their distribution.
We will employ directed content analysis (33) to examine the textual data, with the flexibility to uncover emergent codes as well. To examine the data extracted from the guidelines/HTAs, two coders will each perform iterative rounds of analysis. Following the initial extraction, the case studies will be elucidated, and distinct themes will be identified within different categories of studies (e.g., guideline topics, methods papers, etc.). As we go through the coding process, they will underline the important and relevant sections in the text and choose a term, phrase, or description to best capture its meaning. The codes developed during the pilot phase will serve as predetermined codes in the analysis, with additional codes being added as necessary. Codes sharing similar concepts will be organized into categories. When appropriate, explanations and examples from the text will accompany the codes or categories. The coders will not aim to quantify the frequency of code occurrences. These codes and categories will be utilized to populate the following predefined themes: goods production, goods transport, patient/staff travel, diagnostic tests, facility requirements, IPAC requirements, and disposal impacts. Additional themes will be introduced as required.
The risk of bias and the quality of the studies will be assessed for primary research papers, health guidelines/HTAs using the Risk of Bias In Non-randomized Studies of Exposures/Interventions (ROBINS I/E) tool and Appraisal of Guidelines for Research and Evaluation II (AGREE II) instrument respectively (34–36). The quality of the theoretical or commentary papers included in the scoping review will not be assessed, as it is not typically done in scoping reviews (17, 37).
In our final conclusive assessment, we will present the results of our search using an adapted PRISMA flowchart (19). We will also provide a concise overview of the fundamental attributes of the guidelines included, along with the outcomes of the screening procedure. Results of the analysis will be presented narratively, with codes and classifications for each topic presented in a table, as appropriate, and the quantified data presented in graphs. Any discrepancies or modifications from the established protocol will be duly documented within the final scoping review.