Table 3. Results of the meta-analysis of various indicators.
| Heterogeneity test | Sensitivity analysis | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Factors | Number | Q-test | I2 (%) | Effect model | Effect selection | Effect size and 95%CI | p-value | I2 (%) | p-value | excluded |
| Tuberculosis history | 6 | 0.023 | 61.7% | Random | OR | 3.48 (2.04,5.96) | 0.000 | |||
| Hypertension history | 2 | 0.844 | 0.0% | Fixed | OR | 1.16 (0.80,1.68) | 0.433 | |||
| Diabetes history | 2 | 0.243 | 26.7% | Fixed | OR | 1.44 (0.89,2.34) | 0.134 | |||
| Smoking history | 5 | 0.141 | 42.0% | Fixed | OR | 1.99 (1.54,2.57) | 0.000 | |||
| Smoking index (pack/year) | 5 | 0.000 | 95.5% | Random | SMD | 0.72 (-0.07,1.50) | 0.074 | 95.0% | 0.025 | Yu et al. (12) |
| FEV1/FVC | 6 | 0.000 | 81.7% | Random | SMD | -0.61 (-0.89,-0.32) | 0.000 | |||
| FEV1% | 2 | 0.198 | 39.7% | Fixed | SMD | -0.96 (-1.22,-0.71) | 0.000 | |||
| FEV1%pred | 4 | 0.977 | 0.0% | Fixed | SMD | -0.38 (-0.50,-0.26) | 0.000 | |||
| BMI | 3 | 0.031 | 71.1% | Random | SMD | -0.13 (-0.37,0.11) | 0.280 | 0.0% | 0.003 | Pan et al. (22) |
| Age | 8 | 0.000 | 81.7% | Random | SMD | 0.15 (-0.10,0.39) | 0.233 | |||
| Female sex | 8 | 0.017 | 59.0% | Random | OR | 1.20 (0.80,1.80) | 0.389 | |||
| Mucous sputum | 3 | 0.000 | 90.9% | Random | OR | 0.09 (0.01,1.11) | 0.060 | 82.4% | 0.030 | Martínez-García et al. (8) |
| Purulent sputum | 4 | 0.039 | 64.1% | Random | OR | 5.36 (1.87,15.38) | 0.002 | 68.4% 72.6% |
0.120 0.073 |
Liu et al. (21) / Zhao (23) |
| Purulent mucus sputum | 2 | 0.751 | 0.0% | Fixed | OR | 7.17 (3.85,13.35) | 0.000 | |||
| Positive sputum culture | 2 | 0.638 | 0.0% | Fixed | OR | 1.97 (1.18, 3.29) | 0.009 | |||
| Pseudomonas aeruginosa infection | 7 | 0.916 | 0.0% | Fixed | OR | 5.25 (3.51,7.84) | 0.000 | |||
| Klebsiella pneumoniae infection | 6 | 0.096 | 46.6% | Fixed | OR | 0.91 (0.63,1.34) | 0.644 | |||
| Escherichia coli infection | 4 | 0.747 | 0.0% | Fixed | OR | 1.96 (0.99,3.90) | 0.055 | |||
| Streptococcus pneumoniae infection | 4 | 0.860 | 0.0% | Fixed | OR | 0.84 (0.33,2.15) | 0.710 | |||
| Acinetobacter baumannii infection | 3 | 0.687 | 0.0% | Fixed | OR | 0.78 (0.39,1.58) | 0.488 | |||
| Stenotrophomonas maltophilia infection | 2 | 0.836 | 0.0% | Fixed | OR | 0.23 (0.03,1.88) | 0.169 | |||
| Enterobacter cloacae infection | 2 | 0.865 | 0.0% | Fixed | OR | 1.34 (0.51,3.51) | 0.553 | |||
| Haemophilus infection | 2 | 0.324 | 0.0% | Fixed | OR | 1.49 (0.45,4.94) | 0.517 | |||
| PaCO2 | 3 | 0.003 | 82.5% | Random | SMD | 0.31 (-0.01,0.64) | 0.060 | 0.0% | 0.064 | Liu et al. (21) |
| PaO2 | 3 | 0.518 | 0.0% | Fixed | SMD | -0.14 (-0.27,-0.01) | 0.032 | 23.9% 0.0% |
0.085 0.326 |
Pan et al. (22) / Qin (20) |
| Hospital stay | 3 | 0.749 | 0.0% | Fixed | SMD | 0.41 (0.26,0.56) | 0.000 | |||
| Admission within the past year | 3 | 0.250 | 27.9% | Fixed | OR | 4.25 (2.67, 6.77) | 0.000 | |||
| Duration of symptoms | 2 | 0.554 | 0.0% | Fixed | SMD | 0.31 (0.05,0.57) | 0.018 | |||
| Daily dyspnea | 2 | 0.343 | 0.0% | Fixed | OR | 11.10 (5.92,20.81) | 0.000 | |||
| CRP | 4 | 0.000 | 89.0% | Random | SMD | 0.50 (0.07,0.93) | 0.021 | 91.1% 0.0% |
0.060 0.001 |
Jin et al. (7) / Qin (20) |
| ESR | 3 | 0.000 | 98.5% | Random | SMD | 0.53 (-0.65,1.72) | 0.379 | 0.0% | 0.000 | Liu (21) |
| Hb | 3 | 0.138 | 49.5% | Fixed | SMD | -0.12 (-0.25,0.00) | 0.056 | 0.0% | 0.007 | Qin (20) |
| WBC | 4 | 0.000 | 95.7% | Random | SMD | 0.72 (0.07,1.36) | 0.029 | 0.0% | 0.294 | Qin (20) / Pan et al. (22) |
| N% | 3 | 0.000 | 96.9% | Random | SMD | 0.91 (0.09,1.72) | 0.029 | 95.9% 98.4% |
0.280 0.294 |
Qin (20) / Pan et al. (22) |
| FIB | 4 | 0.000 | 97.3% | Random | SMD | 0.78 (-0.01,1.58) | 0.054 | 80.3% 97.6% |
0.025 0.030 |
Qin (20) / Yu et al. (12) |
| Albumin | 2 | 0.320 | 0.0% | Fixed | SMD | -0.05 (-0.27,0.18) | 0.670 | |||
| Anticholinergic therapy | 2 | 0.536 | 0.0% | Fixed | OR | 1.47 (0.86,2.50) | 0.154 | |||
The blank lines in the sensitivity analysis columns indicate that the results were stable.
BMI, body mass index; CI, confidence interval; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; FEV1/FVC, the ratio between forced expiratory volume in 1 s and forced vital capacity; FEV1%, the percentage of FEV1;. FEV1%pred, FEV1 as a percentage of the predicted value; FIB, plasma fibrinogen; GRADE, grading of recommendations assessment, development, and evaluation; Hb, hemoglobin; N%, percentage of neutrophils; OR, odds ratio; PaCO2, arterial carbon dioxide partial pressure; PaO2, arterial oxygen pressure; SMD, standardized mean difference; WBC, leukocytes