Association of recent clinical respiratory illness with STEMI and high-troponin level in blood among AMI patients:
Multivariate log binomial regression analyses were performed to investigate associations of CRI with occurrence of STEMI and high blood troponin among AMI patients, controlling for potential confounders. All variables deemed clinically relevant as well as having potential confounding effect and also based on P-value were entered in the base model and sequentially removed using a backward stepwise approach whereby variables with P values ≤0.25 remained in the final model. We investigated the aforementioned associations for, 1) entire study period and 2) independently for either the influenza or non-influenza seasons. The magnitudes of association were expressed as relative risk (RR) and adjusted relative risk (aRR) with 95% confidence interval (CI) in unadjusted and adjusted analyses respectively. The SAS statistical software version 9.4 (SAS institute, USA) was used to run the analyses.