Table 2
Meta-analysis results using random effects models
| Model* | |||||
| I | Ib | II | IIb | ||
| Main analyses | n | 18 | 17 | 11 | 10 |
| Study IDs | 1–5b, 6, 8–13, 15–20 | 1, 3–5b, 6, 8–13, 15–20 | 1–5a, 6, 7b, 8, 10, 13, 18 | 1, 3–5a, 6, 7b, 8, 10, 13, 18 | |
| ERR estimate (95% CI) | 0.17 (0.09 to 0.26) | 0.21 (0.11 to 0.33) | 0.16 (0.07 to 0.26) | 0.21 (0.09 to 0.35) | |
| Heterogeneity (between study variance) | Residual: (95% CI) | 0 (<0 to 0.04) | 0 (<0 to 0.05) | 0 (<0 to 0.004) | 0 (not estimable) |
| Cochran's Q, df (p value) | 10.67, 17 (0.87) | 8.96, 16 (0.91) | 3.92, 10 (0.95) | 2.36, 9 (0.98) | |
| Influential study analyses | mDFFITS | ±0.47 | ±0.49 | ±0.60 | ±0.63 |
| N>maxDFFITS (ID, DFFITS) | 1 (2, −0.80) | 0 | 1 (2, −0.83) | 1 (1, −0.76) | |
| Next likely outlier ID (DFFITS, maxDFFITS %) | 1 (0.25, 54%) | 1 (−0.43, 89%) | 1 (0.38, 63%) | 3 (0.12, 19%) | |
| Publication bias | |||||
| Egger's regression | Intercept=0 (p value) | 0.11 (0.031) | 0.14 (0.026) | 0.12 (0.019) | 0.15 (0.032) |
| Trim and fill | Adjusted ERR (95% CI) Studies added | 0.15 (0.07 to 0.23) 5 | 0.18 (0.08 to 0.29) 5 | 0.15 (0.06 to 0.24) 4 | 0.19 (0.07 to 0.32) 3 |
| File drawer | Fail-safe N | 88 | 70 | 28 | 18 |
| Tolerance | 100 | 95 | 65 | 60 | |
↵* Model I prefers single studies to pooled studies, while model II prefers pooled studies to single reports. Model ‘b’ results exclude the outlying study (study no. 2).