Proportion of CRI among patients with AMI:
Out of the 744 AMI patients enrolled during the entire study duration, 84 (11.3%) had reported having CRI during the week prior to AMI onset (Table 2). The majority of participants reporting CRI (77/84; 91.7%) had developed CRI within three days of AMI onset. The most common respiratory symptoms reported during the week preceding AMI were fever (17.9%), cough (16.5%), and runny nose (10.6%). The prevalence of CRI among AMI cases and subgroups varied between influenza and non-influenza seasons, with the highest prevalence observed during the 2017 influenza season (35.7%). During the 2018 influenza season, CRI was more common in recurrent than new onset AMI cases (11.9% vs. 7.3%; p=0.3). Furthermore, during the 2017 influenza season, the prevalence of CRI was higher among STEMI cases than NSTEMI cases (36.8% vs. 33.3%; p=0.8), and prevalence of CRI was higher in STEMI than in NSTEMI cases during the non-influenza season (14.2% vs. 7.3%; p=0.2) and during the 2018 influenza season (7.9% vs. 6.5%; p=0.7). The high-troponin AMI cases had higher rates of CRI compared to low-troponin cases during 2017 (37.5% vs. 35.0%; p=0.9) and during 2018 influenza season (11% vs. 8.7%; p=0.6). Lastly, the percentage of CRI within three days of onset of AMI was higher in recurrent than new onset AMI cases (p=0.15), in high-troponin than low-troponin AMI cases (p=0.6) during 2018 influenza season and higher in STEMI than NSTEMI cases (p>0.05) during both non-influenza and 2018 influenza season.