Statistical analysis
Data analysis was performed in IBM SPSS Statistics for Windows version
22.0 (IBM Corp., Armonk, NY) and Medcalc version 16 (MedCalc Software
bvba, Ostend, Belgium). Shapiro-Wilk test and Kolmogorov-Smirnov test
were used to evaluate the normality of the distribution of numeric data.
The descriptive statistics were presented as frequency with percentage
for categorical variables, median with interquartile range (IQR) for
non-normally distributed numeric data, and mean with standard deviation
(SD) for normally distributed data. The laboratory findings were
compared among the study groups using Independent-Samples Kruskal-Wallis
Test for non-normally distributed numeric data, and One-way ANOVA Test
for normally distributed numeric data. Post-hoc pairwise comparisons
were done using Dunn’s Post-hoc test with Bonferroni correction for
non-normally distributed data. We calculated the difference in median
for determining the effect size in post-hoc pairwise comparison of
laboratory findings among the study groups. Spearman correlation
analysis was used to evaluate the relationships between serum
procalcitonin, lactate, aspartate transaminase (AST) and alanine
transaminase (ALT) levels. Receiver operating characteristic (ROC) curve
analysis was used to estimate the severe disease using serum
procalcitonin and lactate levels. Youden index was used to find the best
cut-off values of these parameters. The AUCs, sensitivity and
specificity with 95% confidence intervals were calculated. A p-value
less than 0.05 was considered statistically significant.