Studies | Bias arising from the randomisation process | Bias due to deviations from intended interventions | Bias due to missing outcome data | Bias in measurement of the outcome | Bias in selection of the reported result | Overall bias |
---|---|---|---|---|---|---|
Andrews et al. 2016 [48] | Low risk | Low risk | Low risk | Some concerns: no information on blinding of outcome assessors | Some concerns: no information on whether statistical analysis was pre-planned | Some concerns |
Bernstein et al. 2015 [47] | Some concerns: Some differences in baseline characteristics between groups | Low risk | Low risk | Low risk | Low risk | Some concerns |
Collins et al. 2019 [49] | Low risk | Low risk | Retention rate relatively low | Â | High risk: authors changed statistical analysis plan due to low retention ratea | High risk |
Curry et al. 2003 [50] | Low risk | Low risk | Low risk | High risk: no biochemical validation in primary outcome | Some concerns: no information on whether statistical analysis was pre-planned | High risk |
Etter et al. 2016 [51] | Some concerns: Some differences in characteristics between groups, but accounted for in analysis | Low risk | Low risk | Low risk | Some concerns: No information on whether statistical analysis was pre-planned | Some concerns |
Gilbert et al. 2017 [46] | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
Glasgow et al. 2000 [52] | Low risk | Low risk | Low risk | Some concerns: no information on blinding of outcome assessors | Some concerns: no information on whether statistical analysis was pre-planned | Some concerns |
Haas et al. 2015 [53] | Low risk | Low risk | Some concerns: Retention rate relatively low and higher assessment rate in control group | High risk: no biochemical validation in primary outcome | Some concerns: no information on whether statistical analysis was pre-planned | High risk |
Manfredi et al. 2004 [54] | Some concerns: differences in racial characteristics between groups | Low risk | Some concerns: Retention rates low, but equally low in both groups | High risk: no biochemical validation in primary outcome | Some concerns: no information on whether statistical analysis was pre-planned | High risk |
Solomon et al. 2000 [55] | Low risk | Low risk | Low risk | Some concerns: no information on blinding of outcome assessors | Some concerns: no information on whether statistical analysis was pre-planned | Some concerns |
Solomon et al. 2005 [56] | Low risk | Low risk | Low risk | High risk: no biochemical validation in primary outcome | Some concerns: no information on whether statistical analysis was pre-planned | High risk |