Evidence mapping – Quantitative synthesis/meta-analysis Systematic review of effectiveness of interventions to reduce carbon-emissions within secondary healthcare: issues with conducting reliable primary research and identifying trustworthy findings

Healthcare services contribute 1% -5% towards global environmental impacts. The Climate Change Act (2008) set targets for the 100% reduction of 1990 carbon emission level in England by 2050.3 Work identifying and delivering interventions to reduce carbon emissions within healthcare supply chains and models of care delivery, is underway.
To complement this work, we aimed to systematically review primary-evidence examining intervention effectiveness in reducing the carbon footprint for medical specialities within secondary healthcare settings. We searched four bibliographic databases covering health care and environmental sciences, including MEDLINE and Embase, Environment Complete and Science Citation Index database. We conducted backward/forward citation searching and searched relevant websites, Google Search, and checked relevant systematic reviews, and the Healthcare Life-cycle Assessment (LCA) database. Two reviewers independently undertook title and abstract and full-text screening, resolving disagreements through discussion. One reviewer data-extracted all studies, and quality-appraised LCA studies with a tool based upon Weideima’s guidelines, which was checked by a second. Findings were tabulated and synthesised narratively.
88 studies (92 articles) met eligibility criteria across five intervention categories: Accessing care (n=39), Product level (n=22), Multiple (n=10), Care Delivery (n=9) and Setting (n=12). Urology (n=14), Gastroenterology (n=13) and Oncology/Radiation oncology (n=13) were the most common specialities represented. 25 articles used LCA methods, with the highest number in urology product-level interventions (n=7). The most common type of intervention was telemedicine (n=26, including 3 LCAs). Studies conducted using LCA and non-LCA methods contained common methodological flaws, making it difficult to accurately determine the systemic impact of interventions intended to reduce carbon-emissions. This has important implications regarding a) ensuring those conducting carbon-emission reduction projects within healthcare settings possess the required skills/knowledge on how to do so b) reflecting on how policy makers can best make use of the evidence available and c) ensuring future research addresses the methodological limitations identified.