Statistical analysis

Data was analyzed using the STATA software version 14.1. Data distribution normality was evaluated using the Shapiro–Wilk test. Data with normal distribution are presented as mean and standard deviation (SD) and data with a non-normal distribution are described as median and interquartile range (IQR). Moreover, qualitative data are expressed as number and percentage.

To compare patients in different groups, t-test, chi-square, and Fisher's exact tests were applied to variables with a normal distribution and Mann–Whitney U test and rank sum test were used for variables with a non-normal distribution. The level of significance was set at 0.05. Logistic regression analysis with odds ratio (OR) and confidence interval was used to evaluate the predictors of mortality in hospitalized patients. In the regression logistic model, the outcome variable was the occurrence of death and other variables were considered as independent variables. First, the variables were entered into a univariate model separately. In case of p < 0.2, they were included in the multivariable model. The multivariable model was done using the “forward” approach. In the multivariable model, adjusted OR was estimated after adjusting for the effect of other variables in the model.