Table 2. Studies which indicate that hypercoagulability (supra-physiological levels of D-dimer), is almost always associated with disease severity and mortality of COVID-19.

Study	Sample size	Mean D-dimer (<0.5 μg/ml)	p-values	Comment
Tang et al, Feb 2020,[34]	Survivors (162)	0.6	<0.001	Disseminated intravascular coagulation (DIC) was found in most deaths
	Non-survivors (21)	2.12
Han et al, Mar 2020, [33]	Ordinary patient (49)	2.14 ±2.88	<0.001	Huge increase in D-dimer in critically ill COVID patients
	Critical (10)	20.04 ± 32.39	<0.05
Wang et al, Mar 2020, [46]	ICU (36)	4.14	<0.001	In the non-survivors, D-dimer increased continuously
	Non-ICU (102)	1.66
Zhang et al, April 2020, [47]	Ordinary (276)	0.41	<0.001	12 non-survivors had D-dimer values greater than 2.0
	Severe (67)	4.76
Spiezia et al, April 2020, [48]	ICU (22)	5.343 ±2.099	<0.0001	All ICU patients with acute respiratory failure showed severe hypercoagulability, one patient with the most hypercoagulable state died.
Ranucci et al, April 2020, [35]	Total (16)	3.5	0.017	Seven patients died of hypoxia and multi-organ failure
Tang et al, May 2020, [49]	Survivors (315)	1.47	<0.001	30 of the non survivors died even after treated with low molecular weight heparin
	Non-survivors (134)	4.7