The impact of heat and cold events on direct, indirect, and intangible healthcare costs : a systematic review

Background Numerous studies have examined the effects of extreme temperatures on healthcare costs. However, most lack a detailed presentation of cost-related findings and often exclude cold-related effects. This systematic review provides a comprehensive overview of the economic burden associated with both heat- and cold-related temperature exposure. Methods Literature published between 2014 and 2024 in English or German was searched in Medline (via PubMed) and the Cochrane Library, supplemented by reference tracking and Internet searches. We included primary studies published in peer-reviewed journals. Two authors independently assessed eligibility and determined a methodological quality score for each included article. Results In total, 39 studies were included: 18 examined heat-related effects, another 18 analyzed combined heat- and cold-related effects, and 3 focused exclusively on cold-related effects. Furthermore, 18 studies focused on direct costs, 1 on indirect costs, 17 on intangible costs, and 3 on multiple cost types. Retrospective studies reported lower annual direct costs per 100,000 persons (mean €678,585; range €43,428–€2.06 million) than prospective studies (mean €1.13 million; range €14,433–€2.02 million). Indirect costs based on retrospective studies averaged €2,287 annually (range €72.75–€8,603), or 19.7 workdays lost per 100,000 persons. Intangible costs were reported using disability-adjusted life years (DALYs), years of life lost, and value of a statistical life. For example, retrospective evidence showed lower annual DALYs per 1,000 persons (mean 1.12; range 0.02–1.82) compared with prospective studies (mean 2.94; range 0.71–11.48). Methodological quality varied between 50 and 79%. Conclusion Extreme temperatures were shown to impact healthcare costs, representing a significant economic burden for healthcare systems. However, findings should be interpreted with caution because of the substantial heterogeneity across studies.