Table 2. Summary of the study design and study characteristics.
| Study | Publication year | Locality | Sample size (T/C) | Quality assessment (NOS score) | Research factors | Age (T/C) | Sex (Male/Female) | Diagnostic criteria | Funder |
|---|---|---|---|---|---|---|---|---|---|
| Qin (20) | 2018 | Jilin | 198/282 | 6 | 1.4.6.8.9.10.11.16.17.18.19.20.22.24.25.26.30.31.32.33.34.35 | 69.88±9.72/ 69.95±9.73 | 257/223 | b (2017 version) HRCT | NA |
| Liu et al. (21) | 2019 | Anhui | 57/96 | 5 | 1.2.3.4.10.11.13.16.17.18.24.25.26.28.30.31.32.33.34 | 69.57±9.64/ 66.34±9.52 | 94/59 | b HRCT | Anhui Provincial Health Department (13ZC024) |
| Pan et al. (22) | 2019 | Shanghai | 135/217 | 6 | 1.2.3.4.6.8.9.10.11.16.17.18.19.20.22.24.25.31.32.33.34.35 | 62.81±10.42/ 64.37±9.15 | 184/168 | a (2013 revision) HRCT | NA |
| Zhao (23) | 2015 | Hebei | 86/114 | 5 | 5.6.7.10.11.12.13.14.15.16.17.18.19.21.27.29 | 67.79±9.27/ 69.48±10.02 | 173/27 | a (2007 revision) b (2011 version) HRCT | NA |
| Jin et al. (7) | 2016 | Beijing | 87/103 | 6 | 1.4.5.8.9.10.11.30.35.36.37 | 77.0/78.9 | 121/69 | clinical diagnosis HRCT | National Natural Science Foundation of China (81170039, 81470239); Beijing Talent Training Foundation (No. 2009D003003000002) |
| Martínez-García et al. (8) | 2011 | Spain | 53/39 | 7 | 1.4.5.6.10.11.12.13.16.28.37 | 72.6/69.1 | 91/1 | clinical diagnosis HRCT | A public grant from the Sociedad Valenciana de Neumología |
| Yu et al. (12) | 2019 | Tianjin | 43/90 | 6 | 1.5.6.8.10.11.16.17.20.21.23.26.27.30.33.35.36 | 71.02±8.47/ 69.78±8.24 | 83/50 | clinical diagnosis HRCT | None |
| Arram et al. (11) | 2012 | Egypt | 33/36 | 7 | 5.6.7.10.11.12.13.14.15.16.17.19.23.27.29 | 63.79±5.41/ 56.50±5.56 | 4/65 | b (2009 version) HRCT | NA |
1. Tuberculosis history 2. Hypertension history 3. Diabetes history 4. Smoking history 5. Smoking index (pack/year) 6. FEV1/FVC 7. FEV1% 8. FEV1%pred 9. BMI 10. Age 11. Female 12. Mucous sputum 13. Purulent sputum 14. Purulent mucus sputum, 15. Positive sputum culture, 16. Pseudomonas aeruginosa infection 17. Klebsiella pneumoniae infection, 18. Escherichia coli infection 19. Streptococcus pneumoniae infection 20. Acinetobacter baumannii infection 21. Stenotrophomonas maltophilia infection 22. Enterobacter cloacae infection 23. Haemophilus infection, 24. PaCO2 25. PaO2 26. Hospital stays 27. Admission within the past year 28. Duration of symptoms 29. Daily dyspnea 30. CRP 31. ESR 32. Hb 33. WBC 34. N% 35. FIB 36. Albumin 37. Anticholinergic therapy.
a. Guidelines for the diagnosis and treatment of chronic obstructive pulmonary disease.
b. The Global Initiative for Chronic Obstructive Lung Disease.
BMI, body mass index; C, control group; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; FEV1/FVC, the ratio between forced expiratory volume in 1s and forced vital capacity; FEV1%, the percentage of FEV1;. FEV1%pred, FEV1 as a percentage of the predicted value; FIB, plasma fibrinogen; Hb, hemoglobin; HRCT, High Resolution Computed Tomography; N%, percentage of neutrophils; NA, unclear or not mentioned; None, no funding; PaCO2, arterial carbon dioxide partial pressure; PaO2, arterial oxygen pressure; WBC, leukocyte; T, trial group.