Examining the Health Impacts of Climate Change Through Electronic Health Records: A Rapid Review

Introduction Temperature extremes, including elevated heat and cold, are important environmental determinants of health whose frequency and duration are increasing due to climate change. Ecological and time-series studies have established links with adverse outcomes but often lack individual-level detail. Electronic health records (EHR) provide an alternative source, yet their use in climate-health research remains inconsistent. Methods We conducted a rapid review of peer-reviewed studies using EHR data to examine associations between temperature extremes and health outcomes across healthcare settings. The aim was to assess how health impacts of temperature extremes have been captured and coded within EHR-based research, and to identify methodological and coding-related gaps. Searches of seven databases identified eligible studies, and data were extracted on exposure definitions, outcome coding, methods, findings, and limitations. Results Of 1,616 records identified, 526 duplicates were removed, leaving 1,090 for screening; 58 studies met inclusion criteria. Extreme heat was most frequently studied, with fewer analyses of cold. Common outcomes included morbidity, cardiovascular admissions, asthma, and pregnancy-related conditions. Mental health outcomes were rarely examined, subgroup analyses were mostly age-based, and studies focused on high-income countries. Exposure metrics and coding practices varied widely, with limited reporting of diagnostic codes and individual-level mediators. Conclusion Harmonized exposure definitions, broader outcome coverage, and integration of socio-demographic and individual-level factors are needed to strengthen EHR-based climate-health research and guide targeted interventions.