Exposure to extreme temperatures disproportionally impacts vulnerable populations, including those with multimorbidity (i.e., people living with two or more long-term health conditions). A greater frequency of temperature extremes such as heatwaves driven by climate change will likely increase adverse health outcomes in vulnerable populations. Therefore, it is important to understand the potential effects of temperature extremes on the health outcomes of multimorbidity populations to aid the planning of healthcare systems and preventive interventions. In this review, evidence was collated and summarised, describing the health outcomes of extreme temperatures amongst people with multimorbidity.

A rapid scoping review with searches on temperature extremes and outcomes in multimorbidity populations was conducted using Medline, CINAHL, Scopus and Wiley Library. These searches were supplemented with manual citation and Google Scholar searches. There were 1,225 titles screened, with data extracted by two independent reviewers. Eight papers were included in the final analysis.

Relatively few studies were identified, indicating limited evidence on this topic. Existing evidence focused on the increased risk of mortality in the multimorbidity population from extreme heat. No studies were identified examining the impact of cold extremes on the health outcomes of those with multimorbidity.

There is a need for significant further research, including systematic review and/or empirical investigation, on a range of issues that can further understanding of the effects of temperature extremes on health outcomes of multimorbidity populations.