Data analysis
To identify potential differences between the distributions of the COVID-19 drug treatment in non-post-COVID-19 syndrome and post-COVID-19 syndrome patients, Pearson’s chi-squared test was used in combination with relative risks to measure the effect size in the univariate analysis. Furthermore, using a binomial logistic regression, the association between corticosteroids, antibiotics, or anticoagulants and the development of the post-COVID-19 syndrome was determined. A p-value of 0.05 or lower was considered to be significant. Missing data was imputed using the expectation maximization method. A missing value of 5% or lower was considered to be acceptable for imputation. Furthermore, data imputation was only necessary in one case. Statistics were performed in R (version 4.0.3) and SPSS (version 28.0.1.0).