PhD Scientific Days 2026

Cardiovascular Medicine and Research 3.

Influence of extreme temperatures on out-of-hospital cardiac arrest cases in Hungary: a national time-series analysis

Name of the presenter

Nagy, Bettina

Institute/workplace of the presenter

Heart and Vascular Centre, Semmelweis University

Authors

Dr. Bettina Nagy¹, Ádám Pál-Jakab MD¹, Boldizsár Kiss MD¹, Endre Zima MD¹
1: Heart and Vascular Centre, Semmelweis University

Text of the abstract

Introduction: Out-of-hospital cardiac arrest (OHCA) remains a major public health challenge. We investigated associations between extreme temperature events and OHCA incidence in Hungary, and explored additional meteorological influences.
Methods: We conducted a national time-series analysis of 116,579 adult OHCA cases (Nov 1, 2018–Dec 31, 2023). Negative binomial regression with cluster-robust standard errors assessed associations between daily OHCA counts and extreme temperatures, adjusting for day-of-week, seasonality, and long-term trends. Added-effect models quantified risk attributable to sustained events while controlling for non-linear temperature–health relationships using natural cubic splines. Distributed lag non-linear models (DLNM) evaluated exposure–lag–response patterns over 21 days.
Results: The temperature–OHCA relationship showed a U-shape with minimum risk at 19.0 °C. Sustained cold spells (≥2 days, daily minimum ≤-9.2 °C; 2nd percentile) showed the greatest risk increase (IRR 1.189; 95% CI: 1.089–1.299; p<0.001). Sustained heatwaves (≥3 days, daily average ≥27.1 °C; 95th percentile) also increased risk (IRR 1.110; 95% CI: 1.032–1.195; p=0.005). Single severe cold days (minimum <-10 °C) were associated with IRR 1.143 (95% CI: 1.012–1.291; p=0.031). DLNM demonstrated distinct temporal patterns: heat effects were acute and transient (peak days 2–4, resolved by day 7), whereas cold effects were delayed and persistent (emerging at day 3, sustained beyond 14 days).
Conclusion: Prolonged extreme temperatures represent independent cardiovascular hazards. Acute heat effects and delayed, sustained cold impacts underscore the need for targeted public health interventions, emergency service preparedness, and timely clinical advisories.
Funding: This work was supported by the Predoctoral Scholarship (Predoktori_2026-32; 16005/DIDIT/2026) and by Project no. TKP2021-EGA-02, implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund under the TKP2021-EGA funding scheme.