Table 2 Risk of bias assessment
All comparisons within studies (N = 164) | |
|---|---|
Randomization | |
High risk | 3 (1.8%) |
Low risk | 110 (67.1%) |
Unclear | 51 (31.1%) |
Allocation concealment | |
High risk | 3 (1.8%) |
Low risk | 74 (45.1%) |
Unclear | 87 (53.1%) |
Performance bias | |
High risk | 75 (45.7%) |
Low risk | 84 (51.2%) |
Unclear | 5 (3.1%) |
Detection bias | |
High risk | 58 (35.4%) |
Low risk | 100 (61.0%) |
Unclear | 6 (3.7%) |
Attrition bias | |
High risk | 51 (31.1%) |
Low risk | 108 (65.9%) |
Unclear | 5 (3.1%) |
Reporting bias | |
High risk | 28 (17.1%) |
Low risk | 136 (82.9%) |
Unclear | 0 (0%) |