Heart failure & cardiomyopathiesResearch article
Cold Spells, Heat Waves, and Nonoptimal Air Temperature and Risk of Heart Failure Hospitalization in Sweden
- Case-crossover study
- nationwide
- time-stratified
- distributed lag nonlinear models
Authors' conclusion
In this Swedish nationwide study, short-term exposure to cold spells, lower temperatures, and higher temperatures was associated with a higher risk of HF hospitalization, with delayed cold effects and more immediate heat effects.
Study context
- Population
- Heart Failure (HF) hospitalizations in the Swedish National Patient Register, 2006–2021
- Participants
- 482,000 HF hospitalizations
- Comparison
- Cold spells, heat waves and nonoptimal temperature vs reference exposure
- Outcome
- HF hospitalization
- Follow-up
- Lag 0-6 days
Main finding
As reported in the abstract
Odds ratio (95% CI)
Cold spellscold season, cumulative lag 2 to 6 days
1.085(1.042–1.129)
Per 10-percentile-point decrease in temperaturecold season, cumulative lag 2 to 6 days
1.008(1.005–1.011)
Per 10-percentile-point increase in temperaturewarm season, cumulative lag 0 to 3 days
1.009(1.006–1.013)
Each row per its own increment, as printed
Original publication
Cold Spells, Heat Waves, and Nonoptimal Air Temperature and Risk of Heart Failure Hospitalization in Sweden. J Am Coll Cardiol. Published 1 September 2026. doi:10.1016/j.jacc.2026.07.008
Summarised from the published abstract; every number is checked against it