| Ref ID | 55 |
| First Author | J. Savović |
| Journal | AMERICAN JOURNAL OF EPIDEMIOLOGY |
| Year Of Publishing | 2018 |
| URL | https://pubmed.ncbi.nlm.nih.gov/29126260/ |
| Keywords |
• Cochrane • Author • Risk of bias • General medical |
| Problem(s) |
• Flawed risk of bias undertaken |
| Article Type | Empirical |
| Article Subtype | Meta-epidemiological analysis |
| First Author Country | United Kingdom |
| Aim | To estimate associations between bias judgements with intervention effect estimates using Bayesian hierarchical models for risk-of-bias judgements (for sequence generation, allocation concealment, blinding, and incomplete data) from a large collection of meta-analyses published in the Cochrane Library (issue 4; April 2011). |
| Level of Investigation | Descriptive |
| Summary of Findings | Bayesian analysis of 228 Cochrane meta-analyses found that intervention effect estimates were, on average, exaggerated in trials with high or unclear (versus low) risk-of-bias judgements for sequence generation (ratio of odds ratios (ROR) = 0.91, 95% credible interval (CrI): 0.86, 0.98), allocation concealment (ROR = 0.92, 95% CrI: 0.86, 0.98), and blinding (ROR = 0.87, 95%CrI: 0.80, 0.93). There was no consistently different bias for subjective outcomes compared with mortality. However, there was an increase in between-trial heterogeneity associated with lack of blinding in meta-analyses with subjective outcomes. Inconsistency in criteria for risk-of-bias judgements applied by individual reviewers is a likely limitation of routinely collected bias assessments. Inadequate randomization and lack of blinding may lead to exaggeration of intervention effect estimates in randomized trials. |
| Number of systematic reviews included | 228 |
| Number of eligible systematic reviews assessed | 4371 |
| Treatment impacted | Yes |
| Treatment impacted description | |
| Interpretation impacted | Yes |
| Interpretation impacted description | Bayesian analysis of 228 Cochrane meta-analyses found that intervention effect estimates were, on average, exaggerated in trials with high or unclear (versus low) risk-of-bias judgements for sequence generation (ratio of odds ratios (ROR) = 0.91, 95% credible interval (CrI): 0.86, 0.98), allocation concealment (ROR = 0.92, 95% CrI: 0.86, 0.98), and blinding (ROR = 0.87, 95%CrI: 0.80, 0.93). There was no consistently different in bias for subjective outcomes compared with mortality. However, there was an increase in between-trial heterogeneity associated with lack of blinding in meta-analyses with subjective outcomes. |