Impact of fine particulate matter (PM2.5) pollution on hospital admissions and mortality due to acute myocardial infarction in Spain.

Introduction and objectives: Atherosclerotic vascular disease is the main cause of mortality attributable to air pollution. This study analyzes, for the first time, the association between levels of fine particulate matter (PM_2.5, particles ≤ 2.5μm in diameter) and hospital admissions and in-hospital mortality due to acute myocardial infarction (AMI) in hospitals of the Spanish National Health System.

Methods: Data on air pollution, temperature, and humidity were obtained from the Ministry for the Ecological Transition and the Demographic Challenge, covering the period from 2016 to 2021. A total of 122 National Health System hospitals were geographically matched with environmental monitoring stations located within a 10km radius. The study included 115 071 patients aged 18 years or older (mean age, 67 years; 28% women) who were discharged with a diagnosis of AMI during the study period. An autoregressive integrated moving average (ARIMA) model was applied to each hospital, and a meta-analysis was conducted to consolidate the estimates of the association between PM_2.5 levels and variations in AMI hospital admissions. The association between PM_2.5 pollution and in-hospital AMI mortality was analyzed using logistic regression models.

Results: Maximum 3-day average PM_2.5 levels exceeding 10μg/m³ were associated with an additional 21.9 AMI hospital admissions per 1000 (95%CI, 9.1-34.8; P<.001). Furthermore, PM_2.5 levels above 25μg/m³ (3-day moving average) were associated with an increased risk of in-hospital mortality due to AMI (OR, 1.14; 95%CI, 1.07-1.23; P<.001).

Conclusions: This study identifies a significant association between elevated PM_2.5 levels and increased hospital admissions and in-hospital mortality due to AMI in Spain, highlighting the importance of reducing air pollution as a critical factor in cardiovascular health.