Association of Pollen Count with Short Term Clinical Outcomes in Different Subtypes of Acute Coronary Syndrome (ACS)

Background: Changes in levels of environmental particulate matter may affect human health such as exacerbation of asthma with severe pollen count. We aimed to assess the association of pollen count as a variable environmental factor with incidence and outcomes of different subtypes of ACS. Methods: We retrospectively reviewed data for 15,379 patients presenting with ACS treated with percutaneous coronary intervention between January 2014 and December 2017 enrolled in the Victorian Cardiac Outcomes Registry. Baseline, clinical and procedural characteristics were analysed and compared with daily pollen count data (low pollen <50 grains/m3, high pollen ≥ 50 grains/m3) of the same period obtained from the Melbourne Pollen Registry. 30-day major adverse cardiac and cerebrovascular events (MACCE) were assessed. Results: Of 15,379 ACS patients, 7,122 were ST-elevation myocardial infarction (STEMI), 6,781 were Non-ST-elevation myocardial infarction (NSTEMI) and 1,476 were unstable angina (UA). Mean age was 62.5 with predominant male gender of 76%. There was no correlation observed between daily pollen count and the incidence of subtypes of ACS (correlation coefficients (r) for all ACS, STEMI, NSTEMI and UA were 0.06, 0.009, 0.083 and 0.003 respectively, all p > 0.05). Similarly, neither high nor low pollen count on the day of ACS presentation was associated with increased odds of in-hospital (OR 1.03, 0.63–1.72; OR 1.01, 0.82–1.24) or 30-day MACCE (OR 0.71, 0.47 −1.07; OR 0.94, 0.81–1.09), all p > 0.05. Conclusions: Variability in daily and seasonal pollen count did not appear to be associated with incidence or clinical outcomes of different subtypes of ACS.