Risk of Myocardial Infarction After Carbon Monoxide Poisoning: A Nationwide Population-Based Cohort Study

Carbon monoxide poisoning (COP) may lead to ischemic changes in organs, and heart is one of the most susceptible targets to ischemic condition. The objective of this study is to evaluate the risk of myocardial infarction following COP. Using a nationwide database of insurance claims in Taiwan, we conducted a population-based cohort study to identify COP patients diagnosed between 1999 and 2012. At a ratio of 3:1, we identified non-COP patients who were matched by the index date and age and compared the risk of myocardial infarction between the two cohorts by time after the index dates of the COP patients, until 2013. We identified 22,258 COP patients and 66,774 non-COP patients. COP patients had an increased risk of myocardial infarction, with an incidence rate ratio of 1.45 (95% confidence interval 1.06-1.98) in comparison with the non-COP patients after adjusting for other independent predictors, including older age, male sex, and underlying comorbidity of hypertension, diabetes, and renal disease. Stratified analyses showed that the increased risk was more prominent in patients with a young age (< 34 years), female sex, and liver disease, and occurred only in the first month of follow-up. We concluded that COP increased the risk of myocardial infarction, but the increased risk was only observed in the first month after COP, which indicated that the impact of COP on the heart was mainly acute. Patients who were younger than 34 years, female, and with liver diseases were more prone to myocardial infarction after COP.