Statistical Analyses
Statistical analyses were performed using the Statistical Package for the Social Sciences for Windows version 22.0 (IBM Corp, Armonk, NY, USA). According to the type of outcomes, the following tests were used to compare severity groups: Kruskal-Wallis, Chi-square and Mann-Whitney U test. Multivariate analysis was used to study the associations between outcomes. Because there were few critical COVID-19 patients, we considered severe and critical forms in a single group for the analyses.