Table 2 Summary of subgroup analysis results
Groups | No. trials | No. patients | RR (95 % CI) | P value | I2, % | P value of heterogeneity |
|---|---|---|---|---|---|---|
All studied | 14 | 1662 | 1.23 (1.05, 1.43) | 0.009 | 83 | < 0.00001 |
Administration route of probiotics | ||||||
 Oral | 5 | 351 | 1.63 (1.19, 2.22) | 0.002 | 71 | 0.008 |
 Vagina | 8 | 1282 | 1.11 (0.96, 1.28) | 0.17 | 79 | < 0.0001 |
 Oral plus Vagina | 1 | 29 | 0.52 (0.24, 1.16) | 0.11 | / | / |
Diagnosis standards | ||||||
 Nugent score | 7 | 579 | 1.01 (0.88, 1.16) | 0.89 | 50 | 0.06 |
 Amsel’s criteria | 4 | 554 | 1.81 (0.90, 3.64) | 0.09 | 96 | < 0.00001 |
 Amsel and/or Nugent score | 3 | 529 | 1.26 (0.96, 2.29) | 0.19 | 84 | 0.002 |
Recruitment area of participants | ||||||
 Europe | 6 | 529 | 1.13 (0.93, 1.38) | 0.21 | 73 | 0.002 |
 Non-Europe | 8 | 1199 | 1.20 (0.95, 1.51) | 0.13 | 87 | < 0.00001 |
Follow-up time | ||||||
 Short-term (≤ 1 month) | 11 | 1149 | 1.21 (1.01, 1.44) | 0.04 | 84 | < 0.00001 |
 Long-term (≥ 1 month) | 3 | 513 | 1.35 (0.87, 2.10) | 0.18 | 85 | 0.001 |
Species of probiotics | ||||||
 Single species | 6 | 995 | 1.19 [0.99, 1.43] | 0.06 | 85 | < 0.00001 |
 Multiple species | 8 | 667 | 1.25 [0.93, 1.69] | 0.14 | 83 | < 0.00001 |
Use of L. rhamnose | ||||||
 Yes | 11 | 987 | 1.28 [1.02, 1.60] | 0.03 | 84 | < 0.00001 |
 No | 3 | 675 | 1.07 [0.92, 1.25] | 0.37 | 64 | 0.06 |
Dosage of probiotics | ||||||
 < 1 × 109 | 7 | 929 | 1.03 [0.94, 1.12] | 0.57 | 42 | 0.11 |
 ≥ 1 × 109 | 7 | 733 | 1.54 [1.13, 2.08] | 0.006 | 77 | 0.0002 |