Seasonality of Selected Cardiovascular Disorders in Austria: A Retrospective Observational Study Between 2009 and 2023

BACKGROUND: Chronoepidemiological patterns in general and seasonality in specific have been investigated for a multitude of pathologies. Although cardiovascular events such as myocardial infarction and stroke are well researched, evidence on other vascular segments and events remains comparably small. METHODS: A retrospective observational study analyzed hospital admission data from 2009 to 2023 for pulmonary embolism (PE), aortic dissection (AD), deep vein thrombosis (DVT), acute limb ischemia, and ruptured abdominal aortic aneurysm. RESULTS: Seasonal variation was most pronounced for PE and AD, with winter peaks and summer troughs (PE 21.5 versus 17.6 admissions/day, -18.2%; AD 2.53 versus 2.06 admissions/day, -18.6%). DVT showed similar fluctuations (peak-to-trough ratio 1.19), whereas acute limb ischemia and ruptured abdominal aortic aneurysm demonstrated smaller absolute variation. Marked weekend effects were observed, with reductions of 65.5% (DVT), 52.5% (PE), 55.2% (acute limb ischemia), and 39.2% (AD); ruptured abdominal aortic aneurysm varied by 15.0%. Although admissions on daylight saving time days were lower than the annual average (eg, PE -42.9%, DVT -52.2%), differences compared with other Sundays were small (mostly <10%), and post-daylight saving time weeks differed by <6% from control weeks. CONCLUSION: This 15-year analysis confirms significant seasonal and weekend effects in vascular emergency admissions, particularly for PE, AD, and DVT. Regional differences in season manifestation and health care access limit generalizability, necessitating context-specific research into underlying mechanisms, including air pollution, health care system characteristics, and behavioral factors, to inform targeted interventions.