Baseline correction and statistical analysis
The propensity score matching (PSM) method was used to screen
symptomatic patients based on the clinical profiles of asymptomatic and
presymptomatic COVID-19 patients upon admission to hospital (16).
Confounding factors include age, gender, hypertension, diabetes,
cardiovascular disease, cerebrovascular disease, cancer, chronic
obstructive pulmonary disease, chronic kidney disease, chronic liver
disease, and immunodeficiency. For continuous variables, the median and
interquartile range (IQR) were used to show the distribution, and the
Wilcoxon rank-sum test with two-sided was used to compare the
differences between groups. Number and percentage were used to show
discrete variables, and Fisher’s exact test with two-sided was used to
compare the differences. All statistical analyses were performed using R
software.