Table 1

Study characteristics, outcomes and laboratory biomarkers

Study	Country	Sample size (n)	Study period	Mean/median age (years)	Male (n)	Study design	Outcome	Laboratory biomarkers
Huang et al 43	China	41	16 Dec 2019 to 2 Jan 2020	49	30	Prospective single-centre	ICU vs non-ICU	Lymphocyte count, AST, PCT, LDH, CK, creatinine and platelet count
Guan et al 5	China	1099	11 Dec 2019 to 29 Jan 2020	47	637	Retrospective multicentre	Severe vs non-severe*	Lymphocyte count, ALT, AST, CRP, PCT, LDH, CK, creatinine, D-dimer and platelet count
Wang et al 56	China	138	1 Jan 2020 to 28 Jan 2020	56	75	Retrospective single-centre	ICU vs non-ICU	PCT
Zhang et al 57	China	140	16 Jan 2020 to 3 Feb 2020	57	71	Retrospective single-centre	Severe vs non-severe†	Lymphocyte count, CRP, PCT, CK and D-dimer
Wang et al 58	China	69	16 Jan 2020 to 29 Jan 2020	42	32	Retrospective single-centre	SpO₂ <90 vs SpO₂ >=90	Lymphocyte count, ALT, AST, CRP, PCT and LDH
Zhou et al 59	China	191	29 Dec 2019 to 31 Jan 2020	56	119	Retrospective multicentre cohort	Survivor vs non-survivor	Lymphocyte count, ALT, platelet count, LDH, CK, PCT, creatinine and D-dimer
Chen et al 46	China	21	Late Dec 2019 to 27 Jan 2020	56	17	Retrospective single-centre	Severe vs moderate†	Lymphocyte count, AST, CRP, PCT, LDH and platelet count
Zheng et al 60	China	161	17 Jan 2020 to 7 Feb 2020.	45	80	Retrospective single-centre	Severe vs non-severe†	Lymphocyte count, ALT, AST, CRP, LDH, CK, creatinine and platelet count
Colaneri et al 61	Italy	44	21 Feb 2020 to 28 Feb 2020	67.5	28	Retrospective single-centre	Severe vs mild‡	Lymphocyte count, CRP, platelet count, LDH and creatinine
Zhao et al 62	China	91	16 Jan 2020 to 10 Feb 2020	46	49	Retrospective single-centre	Severe vs mild§	Lymphocyte count, ALT, AST, CRP, CK, D-dimer, PCT and creatinine
Paranjpe et al 63	USA	1078	27 Feb 2020 to 2 Apr 2020	75 vs 59	627	Retrospective multicentre	In-hospital mortality vs discharged alive	CRP, PCT, and D-dimer
Goyal et al 64	USA	393	3 Mar 2020 to 10 Apr 2020	62.2	238	Retrospective multicentre	IMV vs no IMV	Lymphocyte count, CRP, platelet count, ALT, AST, creatinine, PCT and D-dimer,
Wan et al 65	China	135	23 Jan 2020 to 8 Feb 2020	47	72	Retrospective single-centre	Severe vs mild†	Lymphocyte count, AST, CK, PCT, creatinine and platelet count
Zhang et al 66	China	663	11 Jan 2020 to 6 Feb 2020	55.6	321	Retrospective cohort	Severe and critical vs mild and moderate†	Lymphocyte count, ALT, AST, CRP and LDH
Zheng et al 67	China	34	22 Jan 2020 to 5 Mar 2020	66	23	Retrospective single-centre	IMV vs no IMV¶	Lymphocyte count
Hong et al 68	South Korea	98	Upto Mar 2020	55.4	38	Retrospective single-centre	ICU vs non-ICU	Lymphocyte count, CRP, platelet count, ALT, AST, PCT, LDH, CK and creatinine
Huang et al 69	China	202	22 Jan 2020 to 10 Feb 2020	44	116	Retrospective multicentre	Severe vs non-severe†	Lymphocyte count, CRP and PCT
Wang et al 20	China	65	Jan 2020	57.11	37	Prospective single-centre	(Severe+extremely severe) vs mild†	Lymphocyte count, CRP, PCT, LDH, creatinine and D-dimer
Du et al 70	China	179	25 Dec 2019 to 7 Feb 2020	57.6	97	Prospective single-centre case cohort	Deceased vs survived	Lymphocyte count, AST, CRP, PCT, creatinine and D-dimer
Deng et al 71	China	65	Until 12 Apr 2020	32.5 vs 35	36	Retrospective cohort study	(Severe+critical) vs moderate†	Lymphocyte count, ALT, AST, CRP, LDH, creatinine and D-dimer
Jang et al 72	Korea	110	19 Feb 2020 to 15 Apr 2020	56.9	48	Retrospective single-centre	Severe vs non-severe**	Lymphocyte count, CRP, platelet count, ALT, AST, PCT, LDH, CK, creatinine and D-dimer
Khamis et al 73	Oman	63	24 Feb 2020 to 24 Apr 2020	48	53	Retrospective case series	ICU vs non-ICU	Lymphocyte count, CRP, platelet count, LDH, creatinine and D-dimer
Mikami et al 74	USA	2820	13 Mar 2020 to 17 Apr 2020	62 vs 76	1611	Retrospective multicentre cohort	Survivor vs non-survivor	Lymphocyte count, ALT, AST, CRP, LDH, D-dimer and PCT
Shahriarirad et al 75	Iran	113	20 Feb 2020 to 20 Mar 2020	53.75	71	Retrospective multicentre	Severe vs non-severe*	Lymphocyte count, CRP, platelet count and creatinine
Wang et al 76	China	275	20 Jan 2020 to 10 Feb 2020	49	128	Retrospective single-centre	Severe vs non-severe†	Lymphocyte count, AST, LDH, CK, creatinine and D-dimer
Zhang et al 77	China	221	2 Jan 2020 to 10 Feb 2020	55	108	Retrospective single-centre	Severe vs non-severe†	Lymphocyte count and PCT
Jiang et al 78	China	59	Feb and Mar 2020	64	29	Retrospective multicentre	ICU vs non-ICU	Lymphocyte count, AST, platelet count, CK and creatinine
Li et al 79	China	548	26 Jan 2020 to 5 Feb 2020	60	279	Ambispective cohort study	Severe vs non-severe*	Lymphocyte count, CRP, platelet count, ALT, AST, PCT, LDH, creatinine and D-dimer
Wei et al 80	China	276	27 Jan 2020 to 11 Mar 2020	51	155	Retrospective single-centre	Severe vs non-severe†	Lymphocyte count, CRP, platelet count, ALT, AST, PCT, LDH, CK, creatinine and D-dimer
Xu et al 81	China	239	12 Jan 2020 to 3 Feb 2020	62	143	Retrospective multicentre	Survivor vs non-survivor	Lymphocyte count, platelet count
Zhang et al 82	China	788	17 Jan 2020 12 Feb 2020	Severe—55 Critical—70 Mild—37	407	Retrospective single-centre	(Severe+critical) vs mild†	Lymphocyte count, AST, platelet count and LDH
Ferguson et al 83	USA	72	13 Mar 2020 to 2 May 2020	60.4	38	Retrospective multicentre	ICU vs non-ICU	CRP, PCT, D-dimer
Total		10 491

*Using the American Thoracic Society guidelines for community-acquired pneumonia.
†WHO and the National Health Commission of China interim guidelines defined disease severity and improvement as follows: Mild cases: the mild clinical symptoms and no pneumonia in imaging. Moderate cases: symptoms like fever and respiratory tract symptoms and so on, and pneumonia can be seen in imaging. Severe cases: meeting any of the following—respiratory distress, respiratory rate ≥30 breaths/min; SpO₂ ≤93% at rest; and PaO₂/FIO₂≤300. Patients with >50% lesion progression within 24–48 hours. Critical/extremely severe cases: if they have one of the following: respiratory failure requiring mechanical ventilation, shock and other organ failure requiring ICU treatment.
‡Patients were included in the mild disease group if they did not need high-flow oxygen support and in the severe disease group if they were provided with high-flow oxygen support.
§Not mentioned.
¶Non-invasive mechanical ventilation (NIV) included nasal oxygen therapy, mask oxygen inhalation and high-flow nasal cannula (HFNC).
**Severe disease was defined as a composite outcome of acute respiratory distress syndrome (ARDS), intensive care unit care, or death. ARDS was diagnosed according to the Berlin definition. SARS-CoV-2 infection was confirmed by real-time reverse transcription PCR assay of nose and/or throat swab samples.
ALT, alanine aminotransferase; AST, aspartate aminotransferase; CK, creatine kinase; CRP, C reactive protein; ICU, intensive care unit; IMV, invasive mechanical ventilation; LDH, lactate dehydrogenase; PCT, procalcitonin.