Characteristics of randomised controlled trials (RCTs) included in our study (n=119) associated with high or unclear risk of bias
| Language | Funding source disclosed | Affiliation* | Power calculation included† | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Year of publication | Sample size | Number of authors | English | Chinese | Yes | No | University | Federal/state | Yes | No | |
| Selection bias (sequence generation) | |||||||||||
| Univariate OR (95% CI) | 0.79 (0.70 to 0.88) | 0.99 (0.99 to 1.0) | 0.85 (0.75 to 0.96) | REF | 2.6 (0.94 to 7.2) | REF | 7.7 (3.0 to 19.8) | REF | 1.6 (0.74 to 3.6) | REF | 2.2 (0.13 to 36.7) |
| p Value | 0.0001 | 0.3 | 0.01 | 0.07 | <0.0001 | 0.2 | 0.6 | ||||
| Multivariable OR (95% CI) | 0.83 (0.73 to 0.94) | REF | 5.0 (1.8 to 13.8) | ||||||||
| p Value | 0.003 | 0.002 | |||||||||
| Selection bias (allocation concealment) | |||||||||||
| Univariate OR (95% CI) | 0.90 (0.77 to 1.1) | 0.99 (0.99 to 1.0) | 0.85 (0.75 to 0.96) | REF | 7.4 (1.9 to 29.0) | REF | 4.0 (1.1 to 14.9) | REF | 1.1 (0.29 to 4.2) | REF | 11.4 (0.66 to 197.6) |
| p Value | 0.2 | 0.1 | 0.01 | 0.004 | 0.04 | 0.9 | 0.09 | ||||
| Multivariable OR (95% CI) | 0.85 (0.75 to 0.96) | ||||||||||
| p Value | 0.01 | ||||||||||
| Performance bias | |||||||||||
| Univariate OR (95% CI) | 0.87 (0.75 to 1.0) | 0.99 (0.99 to 1.0) | 0.83 (0.73 to 0.95) | REF | 7.9 (2.1 to 28.5) | REF | 4.1 (1.2 to 14.0) | REF | 1.2 (0.36 to 4.0) | REF | 51.2 (1.2 to 2224.3) |
| p Value | 0.08 | 0.2 | 0.007 | 0.002 | 0.02 | 0.8 | 0.04 | ||||
| Multivariable OR (95% CI) | 0.83 (0.73 to 0.95) | ||||||||||
| p Value | 0.007 | ||||||||||
| Attrition bias | |||||||||||
| Univariate OR (95% CI) | 0.83 (0.74 to 0.93) | 1.0 (0.99 to 1.0) | 0.68 (0.56 to 0.82) | REF | 2.7 (0.96 to 7.7) | REF | 3.1 (1.2 to 7.6) | REF | 1.5 (0.66 to 3.5) | REF | 15.0 (0.36 to 633.8) |
| p Value | 0.002 | 0.7 | 0.0001 | 0.06 | 0.02 | 0.3 | 0.2 | ||||
| Multivariable OR (95% CI) | 0.68 (0.56 to 0.82) | ||||||||||
| p Value | 0.0001 | ||||||||||
| Reporting bias | |||||||||||
| Univariate OR (95% CI) | 0.91 (0.83 to 1.0) | 0.99 (0.99 to 1.0) | 0.86 (0.76 to 0.98) | REF | 4.9 (1.5 to 16.0) | REF | 3.5 (1.4 to 8.9) | REF | 2.7 (1.3 to 5.8) | REF | 5.8 (0.14 to 243.8) |
| p Value | 0.06 | 0.3 | 0.03 | 0.008 | 0.008 | 0.01 | 0.4 | ||||
| Multivariable OR (95% CI) | REF | 4.1 (1.2 to 13.6) | REF | 3.0 (1.1 to 7.7) | |||||||
| p Value | 0.02 | 0.03 | |||||||||
*Two RCTs written by authors affiliated with the State and a University were considered part of the University for this analysis.
†Logistic regression analysis for detection bias was not performed owing to the small number of RCTs that included power calculation (n=2).