Recording and monitoring deaths during heatwaves: a scoping review of mortality attribution and surveillance systems

BACKGROUND: Heatwaves are a significant public health concern linked to substantial excess mortality worldwide. Most deaths during heatwaves arise from the exacerbation of underlying chronic conditions rather than direct heat-related causes, making individual attribution challenging. Improving how heatwave-associated deaths are recorded and monitored is essential for enhancing data quality, comparability, and public health response. OBJECTIVE: To map and synthesise global practices for recording and monitoring heatwave-related mortality, including attribution methods, ICD coding, and integration of real-time surveillance. METHODS: A scoping review was conducted following Joanna Briggs Institute methodology and the Population-Concept-Context framework. Searches were performed in PubMed, Scopus, CINAHL, Embase, and Web of Science from inception. Two reviewers independently screened and extracted data on mortality attribution, ICD coding, recording systems, managing agencies, surveillance approaches, heatwave definitions, limitations, and recommendations. Findings were synthesized using tables, figures, conceptual maps, and narrative summaries. The protocol was registered in the Open Science Framework (OSF) https://doi.org/10.17605/OSF.IO/5AX4T. RESULTS: A total of 176 studies from 41 countries were included. Only 8.5% of the included studies used heat-specific ICD codes to identify direct heat-related death; real-time mortality monitoring systems were limited, fragmented, and inconsistent across jurisdictions. CONCLUSIONS: Heatwave-associated deaths are rarely coded as direct heat-related, reflecting the indirect and multifactorial pathways linking heat to mortality. Significant gaps in global mortality recording and surveillance systems highlight the need for improved attribution practices, standardised coding, integrated systems, and stronger institutional coordination to support public health preparedness in a warming climate.