Statistical analysis
Data were coded and entered using the statistical package for the Social Sciences (SPSS) version 26 (IBM Corp., Armonk, NY, USA). Data was summarized using mean, standard deviation, median, minimum and maximum in quantitative data and using frequency (count) and relative frequency (percentage) for categorical data. Comparisons between quantitative variables were done using the non-parametric Mann-Whitney test. For comparison of serial measurements within each patient the non-parametric Wilcoxon signed rank test was used (Chan, 2003a)(1) . For comparing categorical data, Chi square (χ2) test was performed. Exact test was used instead when the expected frequency is less than 5 (Chan, 2003b)(2) . Correlations between quantitative variables were done using Spearman correlation coefficient (Chan, 2003c)(3) . Logistic regression was done to detect independent predictors of mortality (Chan, 2004)(4) . P-values less than 0.05 were considered as statistically significant.