Table 1

Study characteristics, outcomes and laboratory biomarkers

StudyCountrySample size (n)Study periodMean/median age (years)Male (n)Study designOutcomeLaboratory biomarkers
Huang et al43China4116 Dec 2019 to 2 Jan 20204930Prospective single-centreICU vs non-ICULymphocyte count, AST, PCT, LDH, CK, creatinine and platelet count
Guan et al5China109911 Dec 2019 to 29 Jan 202047637Retrospective multicentreSevere vs non-severe*Lymphocyte count, ALT, AST, CRP, PCT,
LDH, CK, creatinine, D-dimer and platelet count
Wang et al56China1381 Jan 2020 to 28 Jan 20205675Retrospective single-centreICU vs non-ICUPCT
Zhang et al57China14016 Jan 2020 to 3 Feb 20205771Retrospective single-centreSevere vs non-severe†Lymphocyte count, CRP,
PCT, CK and D-dimer
Wang et al58China6916 Jan 2020 to 29 Jan 20204232Retrospective single-centreSpO2 <90 vs SpO2 >=90Lymphocyte count, ALT, AST, CRP, PCT and LDH
Zhou et al59China19129 Dec 2019 to 31 Jan 202056119Retrospective multicentre cohortSurvivor vs non-survivorLymphocyte count, ALT, platelet count, LDH, CK, PCT, creatinine and D-dimer
Chen et al46China21Late Dec 2019 to 27 Jan 20205617Retrospective single-centreSevere vs moderate†Lymphocyte count, AST, CRP, PCT, LDH and platelet count
Zheng et al60China16117 Jan 2020 to 7 Feb 2020.4580Retrospective single-centreSevere vs non-severe†Lymphocyte count, ALT, AST, CRP, LDH, CK, creatinine and platelet count
Colaneri et al61Italy4421 Feb 2020 to 28 Feb 202067.528Retrospective single-centreSevere vs mild‡Lymphocyte count, CRP, platelet count, LDH and creatinine
Zhao et al62China9116 Jan 2020 to 10 Feb 20204649Retrospective single-centreSevere vs mild§Lymphocyte count, ALT, AST, CRP, CK, D-dimer, PCT and creatinine
Paranjpe et al63USA107827 Feb 2020 to 2 Apr 202075 vs 59627Retrospective multicentreIn-hospital mortality vs
discharged alive
CRP, PCT, and D-dimer
Goyal et al64USA3933 Mar 2020 to 10 Apr 202062.2238Retrospective multicentreIMV vs
no IMV
Lymphocyte count, CRP, platelet count, ALT, AST, creatinine, PCT and D-dimer,
Wan et al65China13523 Jan 2020 to 8 Feb 20204772Retrospective single-centreSevere vs mild†Lymphocyte count, AST, CK, PCT, creatinine and platelet count
Zhang et al66China66311 Jan 2020 to 6 Feb 202055.6321Retrospective cohortSevere and critical vs
mild and moderate†
Lymphocyte count, ALT, AST, CRP and LDH
Zheng et al67China3422 Jan 2020 to 5 Mar 20206623Retrospective single-centreIMV vs
no IMV¶
Lymphocyte count
Hong et al68South Korea98Upto Mar 202055.438Retrospective single-centreICU vs non-ICULymphocyte count, CRP, platelet count, ALT, AST, PCT, LDH, CK and creatinine
Huang et al69China20222 Jan 2020 to 10 Feb 202044116Retrospective multicentreSevere vs
non-severe†
Lymphocyte count, CRP and PCT
Wang et al20China65Jan 202057.1137Prospective single-centre(Severe+extremely severe) vs
mild†
Lymphocyte count, CRP,
PCT, LDH, creatinine and D-dimer
Du et al70China17925 Dec 2019 to 7 Feb 202057.697Prospective single-centre case cohortDeceased vs survivedLymphocyte count, AST, CRP, PCT, creatinine and D-dimer
Deng et al71China65Until 12 Apr 202032.5 vs 3536Retrospective cohort study(Severe+critical) vs moderate†Lymphocyte count, ALT, AST, CRP, LDH, creatinine and D-dimer
Jang et al72Korea11019 Feb 2020 to 15 Apr 202056.948Retrospective single-centreSevere vs non-severe**Lymphocyte count, CRP, platelet count, ALT, AST, PCT, LDH, CK, creatinine and D-dimer
Khamis et al73Oman6324 Feb 2020 to 24 Apr 20204853Retrospective case seriesICU vs non-ICULymphocyte count, CRP, platelet count, LDH, creatinine and D-dimer
Mikami et al74USA282013 Mar 2020 to 17 Apr 202062 vs 761611Retrospective multicentre cohortSurvivor vs non-survivorLymphocyte count, ALT, AST, CRP, LDH, D-dimer and PCT
Shahriarirad et al75Iran11320 Feb 2020 to 20 Mar 202053.7571Retrospective multicentreSevere vs non-severe*Lymphocyte count, CRP, platelet count and creatinine
Wang et al76China27520 Jan 2020 to 10 Feb 202049128Retrospective single-centreSevere vs non-severe†Lymphocyte count, AST, LDH, CK, creatinine and D-dimer
Zhang et al77China2212 Jan 2020 to 10 Feb 202055108Retrospective single-centreSevere vs non-severe†Lymphocyte count and PCT
Jiang et al78China59Feb and Mar 20206429Retrospective multicentreICU vs non-ICULymphocyte count, AST, platelet count, CK and creatinine
Li et al79China54826 Jan 2020 to 5 Feb 202060279Ambispective cohort studySevere vs non-severe*Lymphocyte count, CRP,
platelet count, ALT, AST, PCT, LDH, creatinine and D-dimer
Wei et al80China27627 Jan 2020 to 11 Mar 202051155Retrospective single-centreSevere vs non-severe†Lymphocyte count, CRP,
platelet count, ALT, AST, PCT, LDH, CK, creatinine and D-dimer
Xu et al81China23912 Jan 2020 to 3 Feb 202062143Retrospective multicentreSurvivor vs non-survivorLymphocyte count, platelet count
Zhang et al82China78817 Jan 2020 12 Feb 2020Severe—55
Critical—70
Mild—37
407Retrospective single-centre(Severe+critical) vs mild†Lymphocyte count, AST,
platelet count and LDH
Ferguson et al83USA7213 Mar 2020 to 2 May 202060.438Retrospective multicentreICU vs non-ICUCRP, PCT, D-dimer
Total10 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.