Table 7.
Examples of curious supporting explanations for attrition bias judgments that may not appear to be suitable for judging this risk of bias domain
| Study number | Support for judgment | Judgment for risk of attrition bias |
|---|---|---|
| 82 | Chinese article - unable to ascertain | Unclear |
| 144 | This study was a feasibility study. Only 1 woman received the intervention. This study contributed no data to the review. | Unclear |
| 255 | No pre-published protocol identified | High or unclear |
| 256 | If we assume a person works for 40 h per week, then for 28 participants the working hours will be 8960 h for 8 weeks (4 weeks intervention and 4 weeks control period). However the study reported only 7729 working hours based on accelerometer data | High |
| 376 | This is not clear from the paper. Author contacted, but when he moved jobs, the data files for this study were deleted | Unclear |
| 490 | 137 minus 28 equals 109, not 108 | Unclear |
| 492 | Exact time periods of ‘before and after’ accident data were unclear. Authors reported that they “should be 3 to 5 years”. | Unclear |
| 494 | 1 - A reasonable account of how attrition was dealt with is given, but no specific reference to CONSORT | Low |
| 517 | Documented evidence that the CONSORT guidelines have been followed | Low |
| 606 | Data sparse largely narrative style | Unclear |
| 699 | Numbers do not always add up - query if N for outcomes are based on those who answered specific questions on follow-up? | High |
| 727 | Data of drop-outs was censored. | Low |
| 730 | Eleven patients were withdrawn before random assignment: 1 declined further participation, 8 were withdrawn by their physician, and 2 did not meet the entry criteria | Low |
| 744 | Publication is in German and our translation is incomplete. | Unclear |
| 835 | Differences in baseline characteristics of questionnaire responders vs non-responders (western ethnicity in 81% vs 54%, mean age 31 vs 28 years, median blood loss 1500 vs 1150 mL). Big difference in compliance to allocated treatment: 8 vs 34. The design of this trial carries a high risk for selecting the study population | High |
| 838 | Primary and secondary endpoints not specified directly but do address aims | Low |
| 849 | “The situations to consider eliminating the subject from data analysis did not arise” | Low |
| 850 | No Table 1 to clearly describe participant characteristics. | High |
| 854 | Duration of study not defined | High |
| 854 | Criteria for kidney disease not defined | Unclear |
| 873 | Denominators inconsistent in study | Unclear |