Table 4: Risk-of-bias assessment of the trials included in the meta-analysis* .
Trial | Sequence generation (selection bias) | Allocation concealment (selection bias) | Blinding of participants and personnel (performance bias) | Blinding of outcome assessors (detection bias) | Completeness of outcome data (attrition bias) | Selective reporting (reporting bias) | Academic bias | Sponsor bias | |
---|---|---|---|---|---|---|---|---|---|
ADOPT, 200620–26 |
Low |
Low |
Low |
Low |
Low |
Low |
Low |
High |
|
Campbell et al., 199427 |
Unclear |
Unclear |
High |
High |
Low |
Unclear |
Low |
Unclear |
|
Collier et al., 198928 |
Unclear |
Unclear |
High |
High |
Unclear |
Unclear |
Low |
High |
|
DeFronzo et al., 199529 |
Unclear |
Unclear |
Unclear |
Unclear |
Unclear |
Unclear |
Low |
High |
|
Derosa et al., 200442 |
Unclear |
Unclear |
High |
High |
Low |
Unclear |
Low |
Unclear |
|
Hermann et al., 1991a30 |
Low |
Unclear |
High |
High |
Unclear |
Unclear |
Low |
High |
|
Hermann et al., 1991b31–34 |
Low |
Low |
Low |
Low |
Low |
Low |
High |
High |
|
Kamel et al., 199735 |
Unclear |
Unclear |
Unclear |
Unclear |
Unclear |
Unclear |
Low |
Unclear |
|
Lawrence et al., 200436 |
Unclear |
Unclear |
High |
Low |
Low |
Unclear |
Low |
High |
|
Tang et al., 200441 |
Unclear |
Unclear |
High |
High |
Unclear |
Unclear |
Low |
Low |
|
Tessier et al., 199937 |
Unclear |
Unclear |
High |
High |
Low |
Unclear |
Low |
High |
|
Tosi et al., 200338 |
Low |
Low |
Low |
Low |
Unclear |
Low |
Low |
High |
|
UKPDS 34, 19982,39,40 |
Low |
Low |
High |
Low |
Unclear |
High |
Low |
High |
|
Yamanouchi et al., 200543 | Low | Low | High | High | Low | Unclear | Low | Unclear |
Note: ADOPT = A Diabetes Outcome Progression Trial, UKPDS = United Kingdom Prospective Diabetes Study. *The Cochrane risk-of-bias tool was used to assess the risk of bias for each study. Low risk = bias, if present, is unlikely to alter the results seriously, unclear risk = bias raises some doubt about the results, high risk = bias may alter the results seriously.10