Statistical analysis
The continuous variables were summarized as medians and interquartile ranges and compared by the Mann-Whitney-Wilcoxon test. The categorical data were summarized using frequencies and percentages and examined by the chi-square test or the Fisher exact test, as appropriate. The logistic regression model was used to assess the odds ratio of treatment with ACEI vs. ARB on the severity of illness and ARDS. The survival curves of COVID-19 patients were assessed by Kaplan-Meier plots using the log-rank test. The Cox proportional hazards regression model was used to determine the hazard ratios of ACEI vs. ARB use on death. All tests were 2-sided, and P-value >0.05 was considered as statistically significant. All analyses were conducted by Stata/SE version 12 (Stata Crop) and GraphPad Prism version 8 (GraphPad Software Inc).