Table 3.

The summary estimates of comparisons between negative control and different COVID-19 groups

Comparison	Studies	Number of individuals	MD (95% CI)	P-value	Heterogeneity		Egger’s 2-tailed bias p-value	Largest p-value after removing any single study
					P-value	I[2], %
Negative versus positive SARS-CoV-2 groups	4	392/394	−1.48 [−1.74, −1.22]	<0.001	0.817	0	-	<0.001
Mild versus Moderate	2	103/605	−1.09 [−1.58, −0.59]	<0.001	0.319	0	-	<0.001
Non-severe versus Severe	18	2,780/675	−7.14 [−8.67, −5.6]	<0.001	<0.001	95.4	0.009	<0.001
Survived versus Died	7	2,380/290	−15.04 [−23.92, −6.16]	0.001	<0.001	99.1	-	0.034

Abbreviations; CI = confidence interval, MD = mean difference, LR = likelihood ratio. Significant differences are in bold.