Proportions of laboratory confirmed influenza:
Out of 744 participants enrolled in the study, 546 (73.4%) were tested
for influenza by qRT-PCR, and among them only 8 (1.5%) were positive
(Table 2). Of the positive cases, one was confirmed during the 2017
influenza season and seven during the 2018 influenza season. The
identified influenza subtypes were one influenza B/Yamagata during
October 2017, four A/H3 during July, one A/H3 during August, and two
A/H1N1pdm09 during July 2018 influenza season. Influenza virus was
detected exclusively among STEMI cases. Influenza was more prevalent
among recurrent AMI cases than new AMI cases during overall study period
(3.6% vs. 1.2%; 0=0.16) and the 2018 influenza season (4.8% vs.
1.1%; p=0.06). Influenza positivity was higher among AMI cases with
high troponin levels than those with low troponin levels during the 2018
influenza season (2.9% vs. 1.6%; p=0.62).
Proportion of CRI
compared between 2017/2018 non-influenza season and all influenza
seasons:
We compared the proportions of
AMI cases and also sub-groups of AMI cases reporting recent CRI during
the combined duration of annual influenza seasons to that during the
2017/2018 non-influenza season. Among AMI patients with high blood level
of troponin, proportion of CRI was higher during influenza seasons
(16.3%) compared to non-influenza season (3.1%) with p=0.07.
Similarly, NSTEMI patients had a higher proportion of CRI during
influenza season (14.1%) compared to non-influenza season (7.3%) with
a p value of p=0.3.