To increase the sustainability of healthcare, clinical trials must assess the environmental impact of interventions alongside clinical outcomes. This should be guided by Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) and Consolidated Standards of Reporting Trials (CONSORT) extensions, which will be developed by The Implementing Climate and Environmental Outcomes in Trials Group. The objective of the scoping review is to describe the existing methods for reporting and measuring environmental outcomes in randomised trials. The results will be used to inform the future development of the SPIRIT and CONSORT extensions on environmental outcomes (SPIRIT-ICE and CONSORT-ICE).

This protocol outlines the methodology for a scoping review, which will be conducted in two distinct sections: (1) identifying any existing guidelines, reviews or methodological studies describing environmental impacts of interventions and (2) identifying how environmental outcomes are reported in randomised trial protocols and trial results. A search specialist will search major medical databases, reference lists of trial publications and clinical trial registries to identify relevant publications. Data from the included studies will be extracted independently by two review authors. Based on the results, a preliminary list of items for the SPIRIT and CONSORT extensions will be developed.

This study does not include any human participants, and ethics approval is not required according to the Declaration of Helsinki. The findings from the scoping review will be published in international peer-reviewed journals, and the findings will be used to inform the design of a Delphi survey of relevant stakeholders.

Registered with Open Science 28 of February 2025.

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.

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.

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.