Protocol for development of SPIRIT and CONSORT extensions for reporting climate and environmental outcomes in randomised trials (SPIRIT-ICE and CONSORT-ICE)

Abstract

Introduction

The WHO has declared climate change the defining public health challenge of the 21st century. Incorporating climate and environmental outcomes in randomised trials is essential for enhancing healthcare treatments’ sustainability and safeguarding global health. To implement such outcomes, it is necessary to establish a framework for unbiased and transparent planning and reporting. We aim to develop extensions to the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT 2025) and Consolidated Standards of Reporting Trials (CONSORT 2025) statements by introducing guidelines for reporting climate and environmental outcomes.

Methods and analysis

This is a protocol for SPIRIT and CONSORT extensions on reporting climate and environmental outcomes in randomised trials termed SPIRIT-Implementing Climate and Environmental (ICE) and CONSORT-ICE. The development of the extensions will consist of five phases: phase 1—project launch, phase 2—review of the literature, phase 3—Delphi survey, phase 4—consensus meeting and phase 5—dissemination and implementation. The phases are expected to overlap. The SPIRIT-ICE and CONSORT-ICE extensions will be developed in parallel. The extensions will guide researchers on how and what to report when assessing climate and environmental outcomes.

Ethics and dissemination

The protocol was submitted to the Danish Research Ethics Committees, Denmark in June 2025. Ethics approval is expected in September 2025. The SPIRIT and CONSORT extensions will be published in international peer-reviewed journals.

Strengths and limitations of this study.

• The predefined methodology for developing the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 2025 and Consolidated Standards of Reporting Trials (CONSORT) 2025 extensions is based on guidance from the Enhancing the QUAlity and Transparency Of health Research (EQUATOR) Network and follows the development of previous guideline extensions.

• The organisation, consisting of the Implementing Climate and Environmental (ICE) Steering Group, the ICE Group and the ICE Consortium, includes various experts with experience in methodology, randomised trials, environmental impact in clinical research and protocol development for SPIRIT and CONSORT extensions for reporting climate and environmental outcomes in randomised trials, termed SPIRIT-ICE and CONSORT-ICE, respectively.

• Both the SPIRIT-ICE and CONSORT-ICE extensions will be piloted using trial protocols and reports of randomised trials to ensure feasibility and ease of implementation.

• Researchers may face challenges incorporating the final guidelines due to a lack of standardised environmental outcome measures and limited familiarity with available methods to assess climate and environmental outcomes in randomised trials.

Introduction

The accelerating impact of human activities on the environment has reached a serious point.¹ Humanity has transgressed several planetary boundaries, putting the ecosystems at risk of severe instability.¹ The resulting climate and environmental changes increase morbidity and mortality, threatening global health.² As a result, the WHO has identified climate change as the defining public health challenge of the 21st century.³

Healthcare and climate change are interconnected. The healthcare sector is highly resource-intensive and has a substantial carbon footprint, contributing to the increased morbidity and mortality of climate change.² Therefore, healthcare has a responsibility to reduce its climate impact. Most healthcare-related greenhouse gas emissions originate from the supply chain, including the production and distribution of medicines and medical devices used to treat patients.² Thus, to enhance healthcare sustainability and safeguard global health, it is crucial to minimise the environmental impact of medicines, procedures and services.^{4 5}

To enhance the sustainability of healthcare treatments, we propose that environmental considerations should be integrated into the randomised trials that inform healthcare decisions on which interventions to implement just as economic evaluations are integrated.⁶ Therefore, clinical outcomes in trials should be supplemented by outcomes on the environment.^{6 7} Environmental outcomes may include climate impact of the tested interventions, waste, land use, aquatic acidification and ionising radiation (table 1).^{6 7} Thus, interventions are compared not only based on their beneficial and harmful clinical effects but also on their environmental impact and implications for global health.⁶ While clinical decision-making should not be based solely on environmental impacts, such information can be considered where choices exist.

Table 1. Examples of climate and other environmental outcomes.

Outcome	Metric	Example from literature
Climate impact	Kilograms of carbon dioxide equivalents	Nguyen et al9
Waste	Kilograms of waste generated	Nguyen et al9
Land use	Square metres of organically managed arable land	Hemberg et al45
Aquatic acidification	Kilograms of sulphur dioxide equivalents	Hemberg et al45
Ionising radiation	Becquerels of carbon-14 equivalents	Hemberg et al45

The climate and environmental impact of clinical interventions can be quantified using Life Cycle Assessment or similar methods.⁸ A few randomised trials have begun reporting climate and environmental outcomes alongside clinical outcomes,9,13 with Nguyen et al being the only completed trial.⁹ Nguyen et al compared enteral to parenteral phosphate replacement in critically ill patients with hypophosphataemia.⁹ The trial showed that enteral phosphate replacement was non-inferior to parenteral replacement on clinical outcomes, but enteral phosphate replacement led to a lower climate impact.⁹

Planning and reporting randomised trials are complex processes, and introducing new aspects, such as climate and environmental outcomes, increases this complexity, especially when there is a lack of standardised, transparent methods for reporting.¹⁴

To aid researchers in designing and reporting randomised trials, the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) and the Consolidated Standards of Reporting Trials (CONSORT) guidelines have been developed with recommendations for the minimum content of randomised trial protocols and the primary reports of completed randomised trials.^{15 16} Some groups have presented the carbon footprint of the trial processes themselves¹⁷; however, currently, the reporting of climate and environmental outcomes relating to tested interventions is not covered by the SPIRIT 2025 or CONSORT 2025 guidelines or any extensions to previous versions of the guidelines.¹⁸ Thus, extensions addressing these specific areas are needed.

We established the Implementing Climate and Environmental Outcomes in Trials Group (ICE Group), a group of international experts, including methodologists, trialists and practitioners in environmental footprinting.⁶ The group aims to develop SPIRIT and CONSORT extensions for reporting climate and environmental outcomes in randomised trials.⁶ The extensions will be termed SPIRIT-ICE and CONSORT-ICE.^{19 20}

Aims

This paper aims to describe the methods and processes used to develop the SPIRIT-ICE and CONSORT-ICE extensions for reporting climate and environmental outcomes in randomised trials.

Methods

The SPIRIT-ICE and CONSORT-ICE extensions have been registered with the Enhancing the QUAlity and Transparency Of health Research (EQUATOR) Network.^{19 20} The process will follow the recommendations of the EQUATOR Network’s guidance and developments of previous extensions.21,37 The process will consist of five phases: phase 1—project launch, phase 2—review of literature, phase 3—Delphi survey, phase 4—consensus meeting and phase 5—dissemination and implementation (table 2). The phases are expected to overlap. The SPIRIT-ICE and CONSORT-ICE extensions will be developed in parallel.

Table 2. Phases of developing the SPIRIT-ICE and CONSORT-ICE extensions.

Phase	Elements
Phase 1	Registration with the EQUATOR Network Establishing organisation Project launch
Phase 2	Scoping review of current practices Preliminary long list generation
Phase 3	Stakeholder engagement The Delphi process
Phase 4	Consensus meeting
Phase 5	Checklist revision Piloting the checklists Write up Dissemination Implementation

CONSORT, Consolidated Standards of Reporting Trials; EQUATOR, Enhancing the QUAlity and Transparency Of health Research; ICE, Implementing Climate and Environmental Outcomes in Trials; SPIRIT, Standard Protocol Items: Recommendations for Interventional Trials.

Phase 1: project launch

Registration with the EQUATOR Network

As a first step, the SPIRIT and CONSORT extensions on reporting climate and environmental outcomes in randomised trials were registered with the EQUATOR Network in June 2024 and with Open Science on 20 August 2025.^{19 20 38}

Establishing organisation

After registering the project with the EQUATOR Network, we established the organisation around the ICE Group. The organisation consists of a steering group, termed ICE Steering Group, including seven members with experience in methodology, trials, environmental impact assessment in clinical research and conducting SPIRIT and CONSORT extensions (JJP, LH, LT, SH, A-WC, PB and JCJ). The ICE Steering Group oversees the day-to-day management of the project and holds regular virtual meetings to discuss the progress of the project. The ICE Group consists of an additional 15 international experts (AH, OM, SK, NS, PRW, LF, CBK, J-MH, SB, IB, FM, SMA, LM, JSl and JSh) overseeing all aspects and major decisions of the project, contributing with guidance at each phase, assisting with drafting and dissemination, recruiting stakeholders and supporting the reporting guidelines’ distribution. The ICE Consortium consists of additional stakeholders involved in the Delphi process and consensus meeting group. The recruitment of stakeholders for the Delphi process is ongoing and will continue until the start of phase 3. More details on the recruitment of stakeholders are provided below.

Project launch

As a final step in phase 1 to launch the project, the ICE group published a paper in The Lancet in 2024, explaining the need for the SPIRIT and CONSORT extensions to incorporate climate and environmental outcomes in randomised trials.⁶

Phase 2: review of literature

Scoping review of current practices

A scoping review will be performed to identify current practices for reporting climate and environmental outcomes in randomised trials. The protocol for the review has been registered with Open Science³⁹ and submitted for publication in BMJ Open. The scoping review will be performed in two parts: (1) identifying existing guidelines, reviews or methodological studies describing environmental impacts of interventions and (2) identifying how environmental outcomes are reported in trial protocols and completed randomised trials.

In the first part of the review, the EQUATOR Network will be searched for existing SPIRIT and CONSORT extensions to confirm that no overlapping extensions already exist or are being planned. Furthermore, a search will be performed to identify other relevant existing guidelines, reviews or methodological studies describing environmental impacts of interventions. In the second section of the review, a search will be conducted to identify reviews, randomised trial protocols and final reports of trials assessing environmental outcomes. This search will be divided into two components: one focusing on relevant reviews of randomised trials and one targeting relevant randomised trial protocols and trial results. The searches will be conducted by an information specialist. All searches will be performed from their inception to the present date. We expect to run the search at the end of 2025. See online supplemental additional file 1 for the complete search strategy. The results of the searches will be uploaded to Covidence.⁴⁰ Two review authors will perform screening independently.

Data from the included studies will be extracted independently by two review authors. Data will be extracted for study characteristics, intervention characteristics, control characteristics and reporting of climate and environmental outcomes. Results will be presented descriptively and summarised using frequencies and percentages for categorical data and means and SDs for continuous data.

The methodology for the scoping review is described in detail in a protocol submitted to BMJ Open.

Preliminary long list generation

Based on the results of the scoping review of current practices, two preliminary long lists of items for the SPIRIT and CONSORT extensions will be generated: one for the SPIRIT extension and one for the CONSORT extension. The items on the long list will be included in the Delphi survey. Before starting the Delphi survey, members of the ICE Group will review each item on the long list to identify potentially relevant items and exclude those that are irrelevant.

Phase 3: Delphi survey

Stakeholder engagement

To ensure a comprehensive perspective and enhance the credibility and utility of the SPIRIT and CONSORT extensions, a diverse range of stakeholders will be included in the Delphi survey. We pragmatically expect to obtain more than 300 participants with global representation and diversity in age, gender and profession. The aim is to involve the following stakeholders:

• Healthcare professionals.

• Trial investigators (eg, trial clinicians, trial managers, principal investigators, research assistants, site investigators and clinical research nurses).

• Trial methodologists.

• Environmental scientists and practitioners in environmental footprinting (eg, environmental engineers, industrial ecologists, life cycle practitioners and sustainability professionals).

• Patient and public representatives.

• Statisticians.

• Epidemiologists.

• Journal editors.

• Industry representatives.

• Funders.

• Representatives from regulatory agencies.

• Medical ethics experts and representatives from ethics committees.

• Health policy-makers.

Stakeholders will be recruited through the ICE Group network, social media networks, conferences and authors of published papers from the ICE Group on the SPIRIT and CONSORT extensions. All interested stakeholders may register at a website (ice-project.org), which is currently being developed. Following expression of interest at the website, the stakeholders will be contacted through email once the Delphi survey is launched.

The Delphi process

In the Delphi survey, feedback and input from stakeholders on relevant information are collected through a series of survey questionnaires.⁴¹ Each questionnaire will be refined based on comments from previous iterations.⁴² This method is widely used in SPIRIT and CONSORT extensions.22,37 The objectives of the Delphi survey will be (1) to evaluate the agreement of the stakeholders on two reporting checklists, one for trial protocols and one for primary reports of completed randomised trials, with the initial items based on the results of the scoping review (see above), (2) to identify any further items or changes to items already on the list and (3) to identify which items the stakeholders in the Delphi survey find to be the most important. The Delphi survey will be produced online and distributed through email and conducted using a General Data Protection Regulation (GDPR) compliant software.

The Delphi survey will be conducted in three rounds. Each round will be open for responses for 2 weeks, with reminders sent 1 week and 1 day before the deadline. In all three rounds, participants will be presented with two checklists, each containing possible items: one for the SPIRIT extension and one for the CONSORT extension. For each item, participants are asked to rate on a 9-point scale from 1 to 3 (not important), 4–6 (important) and 7–9 (critically important) the extent to which they agree with the inclusion of the item in the SPIRIT extension and CONSORT extension, as in previous SPIRIT and CONSORT extensions.²² A text box for comments will also be available for each item, allowing stakeholders to justify their decisions or suggest changes. Furthermore, a text box at the end of each checklist will be provided for suggestions of new checklist items in the first and second round. Based on previous SPIRIT and CONSORT extensions, each round should take no more than 15–20 min to complete, depending on the level of justification given and new suggestions made. In the first round of the Delphi survey, participants will also be asked to provide demographic information, including age, gender, country, profession and stakeholder group. Participants will be able to select more than one stakeholder group.

Items reaching a high level of agreement will be presented for information purposes only with no voting in the following rounds. A high level of agreement is defined as ≥80% of participants responding rating the item in the same category (ie, not important, important or critically important).³⁷ Thus, this item will be deemed to meet ‘consensus’. Anonymised results from the previous round will be summarised in the following round, including the number of participants who scored the item, the distribution of scores and a synthesis of comments on the items. Results will be presented anonymously both as a summary across all stakeholder groups and separately for each individual stakeholder group. On items not reaching consensus, participants will be invited to review their earlier score considering other participants’ responses.

Following all three rounds of the Delphi survey, results will be summarised. The mean and median scores for each item will be calculated, and the items will be categorised as follows: no consensus (<80% of the participants rate the item in any category); consensus is reached for a rating of not important (1–3); consensus is reached for a rating of important (4–6); consensus is reached for a rating of critically important (7–9). The results of the Delphi survey will be presented during the consensus meeting to inform the selection of final checklist items. Demographic information and completion rates for the second and third rounds of the Delphi survey will also be reported in comparison to round one.

Phase 4: consensus meeting

Consensus meeting

Following the Delphi process, a consensus meeting will be organised, including the ICE Steering Group and key stakeholders with a broad representation of those invited to take part in the Delphi survey. A maximum of 30 participants is expected based on previous SPIRIT and CONSORT extensions. Due to the nature of these SPIRIT and CONSORT extensions, the consensus meeting will be held online using a virtual platform. Before the consensus meeting, all participants will be informed of the scoping review results and the Delphi survey. Afterwards, stakeholders will be invited to indicate their interest in participating in the online consensus meeting. If the number of interested stakeholders exceeds capacity, the ICE Steering Group will select the consensus group to ensure balanced and broad representation across stakeholder groups and demographic characteristics. The main aim of the meeting is to reach a consensus on items to include in the final checklists for reporting climate and environmental outcomes in randomised trials, informed by the Delphi survey. The ICE Steering Group will present background information and provide an update on previous work to facilitate the discussions. Following these discussions, items may be modified, added or removed based on the Delphi survey results and stakeholder input. Consensus will be sought through discussion, with voting implemented if consensus cannot be reached.

Phase 5: dissemination and implementation

Checklist revision

Following the consensus meeting, the format and wording of each item will be reviewed. Afterwards, the draft checklists will be circulated to the participants of the consensus meeting to confirm whether they represent the group consensus or need clarification. Items will be revised in response to feedback to ensure that the final checklist represents the group consensus. If consensus cannot be reached, the steering group will make the final decision, and the lack of consensus will be noted in the final report.

Piloting the checklists

After finalising the checklists, the checklists will be piloted on a sample of published randomised trial protocols and primary reports of completed randomised trials reporting climate and environmental impact. Any feedback will be used to identify practical challenges and to inform the writing of the statement and explanation and elaboration (E&E) document.

Write-up

Following the piloting of the checklists, the ICE Steering Group will lead the writing of the final version of the checklist and the associated guidance statement. This will be circulated to the ICE Group. The guideline statements will be published with detailed E&E documents. The E&E documents will thoroughly explain the scientific rationale for each item, together with an example of clear reporting. The E&E document will be developed with feedback from consensus meeting participants.

Authorship

Authorship will be determined according to the International Committee of Medical Journal Editors standards. Members of the consensus meeting and members of the ICE Group are expected to be authors of the SPIRIT and CONSORT extensions. The ICE Steering Group will ultimately decide authorship. Authorship on the protocol does not ensure authorship on the SPIRIT and CONSORT extensions, and vice versa.

Dissemination

We will seek to disseminate the SPIRIT and CONSORT extensions widely. We will seek multiple simultaneous publications of the SPIRIT and CONSORT extensions and the E&E document in relevant open-access journals. Further dissemination of the extensions will include presentations at medical, trial-related, environmental and healthcare policy conferences. Additionally, the extensions will be presented at editorial forums and to major randomised trial funders, published on the CONSORT and EQUATOR websites, and disseminated through relevant social media channels. We will also consider writing editorials in clinical discipline-specific journals to introduce them to various clinical audiences.

Implementation

To increase the implementation of the guideline extensions, we will contact journal editors to encourage endorsement and implementation of the SPIRIT and CONSORT extensions, as this is associated with better reporting quality.⁴³ Other implementation strategies, including potential alignment with recent WHO guidance on clinical trials,⁴⁴ will be discussed during the consensus meeting.

Ethics and dissemination

The protocol was submitted to the Danish Research Ethics Committees, Denmark in June 2025. Ethics approval is expected in September 2025. The SPIRIT and CONSORT extensions will be published in international peer-reviewed journals. See further description of dissemination above.

Patient and public involvement

A patient and public representative is part of the ICE Group (LM) and is involved in overseeing all aspects and major decisions of the project, with a particular focus on patient and public involvement. Furthermore, patients and public representatives will participate in the conduct of the Delphi survey, the consensus meeting and the dissemination plans of our research. In the Delphi survey, patients and public representatives will be included as stakeholders with equal voting rights and the opportunity to suggest new items of interest, alongside other stakeholder groups. Recruitment will be conducted through the network of the ICE Group, relevant patient organisations, patient and public involvement networks and social media. Snowball sampling will also be employed by asking recruited representatives to recommend others in their network who may be interested. Patients and public representatives will be recruited based on their interest in public and planetary health, without restrictions on age, health status or specific conditions. We aim to ensure broad diversity in gender, cultural background and geographical representation. Patient and public representatives are also expected to participate in the consensus meeting. Their involvement in the consensus meeting will help ensure that patient and public perspectives are meaningfully integrated into decision-making. Furthermore, their input will be sought to inform relevant dissemination strategies.

Discussion

This is a protocol for SPIRIT and CONSORT extensions on reporting climate and environmental outcomes in randomised trials termed SPIRIT-ICE and CONSORT-ICE. The development of the extensions will consist of five phases: phase 1—project launch, phase 2—review of literature, phase 3—Delphi survey, phase 4—consensus meeting and phase 5—dissemination and implementation. The phases are expected to overlap. The SPIRIT-ICE and CONSORT-ICE extensions will be developed in parallel. The extensions will guide researchers on how, when and what to report when assessing climate and environmental outcomes.

This protocol has several strengths. First, the predefined methodology is based on the guidance of the EQUATOR Network and follows the developments of previous extensions.21,36 Second, the organisation, comprising the ICE Steering Group, the ICE Group and the ICE Consortium, includes a diverse range of experts with experience in methodology, trials, environmental impact assessment in clinical research and conducting SPIRIT and CONSORT extensions, thereby ensuring the methodological robustness of the process. Third, the development of SPIRIT-ICE and CONSORT-ICE will include a broad representation of stakeholders to increase the credibility and usefulness of the extensions. Finally, the SPIRIT and CONSORT extensions will be piloted on a sample of published randomised trial protocols and primary reports of completed randomised trials that report climate and environmental outcomes, ensuring their feasibility and ease of implementation.

This protocol also has certain limitations. First, integrating environmental outcomes into randomised trials is a relatively new area. As a result, the preliminary list of potential items for the Delphi survey—and ultimately the SPIRIT and CONSORT extensions—may be based on limited previous data. However, members of the ICE Group and stakeholders participating in the Delphi survey will be able to add additional items to the list for inclusion based on their expertise. Second, it might be challenging for researchers to incorporate the final guidelines due to a lack of available or standardised methods to measure environmental outcomes and limited familiarity with methods to assess climate and environmental outcomes in randomised trials. It is essential that the implementation of the SPIRIT and CONSORT extensions is feasible for trialists. Conducting a randomised trial already demands substantial effort, and the addition of climate outcomes may require consultations with specialised experts in environmental sciences depending on the expertise required for the reporting of climate outcomes and the skillset of the trialists. To address this, we will endeavour to provide recommendations that are both practical to implement and to achieve an appropriate balance between feasibility and the inclusion of key elements related to environmental outcomes. Furthermore, we will pilot the SPIRIT and CONSORT extensions on multiple randomised trial protocols and reports to identify potential implementation challenges. Additionally, the final guideline statements will be published with a detailed E&E document based on the consensus meeting and the piloting of the guidelines. Finally, interpreting climate and environmental outcomes may be challenging, as there is currently no established ethical framework or clear understanding of minimal important differences when evaluating climate and environmental impact in relation to clinical and cost outcomes.

Despite possible challenges in developing and implementing the SPIRIT and CONSORT extensions on climate and environmental outcomes in randomised trials, these guidelines are essential for ensuring unbiased and transparent planning and reporting of the climate and environmental impact of healthcare interventions as measured in clinical trials.