Table 1.
Characteristics of included studies.
| References | Area | Diagnostic criteria | Clinical outcomes | Sample size | Incident cases | Indicators | Effect sizes* | Adjustment |
|---|---|---|---|---|---|---|---|---|
| Aggarwal et al. (4) | India | WHO interim guidance | ICU admission, mechanical ventilation, death | 32 | 12 | Lymphocytes | 0.47 (0.08–2.81) | - |
| Chen et al. (5) | China | Chinese interim guidance; WHO interim guidance | ICU admission | 249 | 22 | Lymphocytes | 4.05 (0.89–18.50) | Age, male, comorbidity, WBC, CRP, albumin, AST, LDH, eGFR |
| CD4+ T cells | 0.55 (0.33–0.92) | |||||||
| Du et al. (6) | China | WHO interim guidance | Death | 179 | 21 | Lymphocytes | 0.273 (0.061–13.415) | - |
| CD8+ T cells | 0.251 (0.071–0.883) | Age, hypertension, cardiovascular or cerebrovascular diseases, dyspnea, fatigue, sputum production, headache, WBC, neutrophils, cTnI, myoglobin, creatinine, D-dimer, blood pressure | ||||||
| Guan et al. (7) | China | WHO interim guidance | ICU admission, mechanical ventilation, death | 879 | 54 | Lymphocytes | 0.38 (0.13–1.06) | - |
| Yun et al. (8) | China | Chinese interim guidance (5th edition) | ICU admission | 292 | 21 | CD3+ T cells | 0.996 (0.991–1.000) | Neutrophils, ALT, AST, albumin, LDH, creatinine, cystatin-C, transferrin, CRP, procalcitonin, D-dimer, creatine kinase, CK-MB, NT-proBNP, cTnI, myoglobin |
| CD8+ T cells | 1.006 (1.001–1.010) | |||||||
| Liu et al. (9) | China | Chinese interim guidance (4th edition) | Disease progression, death | 78 | 11 | Lymphocytes | 0.625 (0.428–65.868) | - |
| Liu et al. (10) | China | WHO interim guidance | Death | 245 | 33 | Lymphocytes | 0.86 (0.34–2.15) | Age, sex, BMI, hypertension, chronic liver disease, HIV infection, COPD, smoking, respiratory rate, ALT, creatinine, PT, D-dimer |
| Luo et al. (11) | China | WHO interim guidance | Death | 1,018 | 201 | CD8+ T cells | 0.169 (0.105–0.272) | Age, sex, hypertension, CHD, diabetes, pulmonary diseases |
| Pan et al. (12) | China | Chinese interim guidance; WHO interim guidance | Death | 124 | 89 | Lymphocytes | 0.249 (0.090–7.550) | Sex, SpO2, breath rate, diastolic pressure, neutrophil, CRP, PCT, LDH, D-dimer |
| Petrilli et al. (13) | USA | WHO interim guidance | ICU admission, mechanical ventilation, discharge to hospice, death | 2,725 | 990 | Lymphocytes | 0.57 (0.40–8.73) | Time, age, sex, race, smoking, BMI, underlying diseases, temperature, SpO2, ALT, AST, CRP, D-dimer, ferritin, PCT, TnI |
| Death | 2,737 | 424 | Lymphocytes | 0.72 (0.55–10.48) | ||||
| Urra et al. (14) | Spain | WHO interim guidance | ICU admission | 172 | 27 | Lymphocytes | 0.769 (0.687–0.861) | - |
| CD8+ T cells | 0.380 (0.152–0.950) | |||||||
| Wu et al. (15) | China | WHO interim guidance | ARDS | 201 | 84 | Lymphocytes | 0.37 (0.21–0.63) | - |
| CD3+ T cells | 0.83 (0.72–0.96) | |||||||
| CD4+ T cells | 0.74 (0.59–0.93) | |||||||
| CD8+ T cells | 0.74 (0.53–1.04) | |||||||
| Death | 84 | 44 | Lymphocytes | 0.51 (0.22–1.17) | - | |||
| CD3+ T cells | 0.81 (0.59–1.11) | |||||||
| CD4+ T cells | 0.83 (0.51–1.35) | |||||||
| CD8+ T cells | 0.51 (0.24–1.09) | |||||||
| Xu et al. (16) | China | Chinese interim guidance (6th edition) | Death | 239 | 147 | Lymphocytes | 0.81 (0.58–12.5) | Age, malignancy, platelet, ARDS, acute cardiac injury, AKI, liver dysfunction, coagulopathy |
| Zhang and Han (17) | China | WHO interim guidance | Death | 409 | 102 | Lymphocytes | 0.012 (0.001–0.128) | Age, sex, diarrhea, WBC, neutrophil |
| CD3+ T cells | 0.968 (0.933–1.004) | - | ||||||
| CD4+ T cells | 1.114 (0.997–1.244) | |||||||
| CD8+ T cells | 0.835 (0.745–0.937) | |||||||
| B cells | 0.979 (0.923–1.039) | |||||||
| NK cells | 0.796 (0.611–1.039) | |||||||
| Zhou et al. (18) | China | WHO interim guidance | Death | 191 | 54 | Lymphocytes | 0.19 (0.02–1.62) | Age, D-dimer, SOFA score, coronary heart disease |
| Zhou et al. (19) | China | Chinese interim guidance (5th edition) | Aggravation | 17 | 5 | Lymphocytes | 0.997 (0.993–0.999) | WBC, CRP, albumin, LDH, D-dimer |
| CD4+ T cells | 0.995 (0.989–1.000) | |||||||
| CD8+ T cells | 0.993 (0.984–1.002) |
WHO, World Health Organization; ARDS, acute respiratory distress syndrome; WBC, white blood cells; CRP, C-reactive protein; PCT, procalcitonin; ALT, alanine aminotransferase; AST, aspartate aminotransferase; LDH, lactate dehydrogenase; eGFR, estimated glomerular filtration rate; cTnI, cardiac Troponin I; BMI, body mass index; COPD, chronic obstructive pulmonary disease; CHD, coronary heart disease; ARDS, acute respiratory distress syndrome; AKI, acute kidney injury; PT, prothrombin time; NT-proBNP, N terminal pro B type natriuretic peptide; SOFA, Sequential Organ Failure Assessment.
*
Effect sizes for the lowest vs. highest lymphocyte levels were adjusted to the highest vs. the lowest.