Table 7.
Assessment of risk of bias.
| Questions | Studies~
|
|||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1.1 | 2.1 | 3.1 | 3.2 | 4.1 | 5.2 | 5.3 | 6.1 | 6.5 | 7.1 | 8.1 | 9.1 | 10.1 | 11.1 | 11.2 | 12.1 | |
| 0. Were concurrent comparison (control) group(s) used? | Y | Y | Y | Y | Y | N | Y | Y | Y | Y | N | N | N | Y | Y | Y |
| 1. Is the hypothesis/aim/objective of the study clearly described? | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| 2. Are the main outcomes to be measured clearly described in the Introduction or Methods section? | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| 3. Are the characteristics of participants included in the study clearly described? | N | Y | Y | Y | N | Y | Y | Y | Y | N | N | N | N | N | N | Y |
| 4. Are the interventions of interest clearly described? | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| 4a. Was the calendar duration of the intervention documented? | N | Y | N | N | Y | Y | Y | Y | Y | N | Y | Y | Y | N | N | N |
| 5. Are the distributions of principal confounders in each group of participants to be compared clearly described? | N | N | Y | N | N | N | Y | Y | Y | N | N | N | N | N | N | N |
| 6. Are the main findings of the study clearly described? | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| 7. Does the study provide estimates of the random variability in the data for the main outcomes? | Y | N | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | N | N | N | N |
| 8. Have all important adverse events that may be a consequence of the intervention been reported? | Y | Y | Y | Y | N | N | N | N | N | N | N | N | N | N | N | N |
| 9. Have the characteristics of participants lost to follow-up been described? | NA | NA | NA | NA | NA | NA | NA | Y | Y | NA | NA | NA | NA | NA | NA | NA |
| 10. Have actual probability values been reported (e.g., 0.035 rather than <0.05) for the main outcomes except where the probability value is less than 0.001? | N | Y | Y | Y | Y | Y | Y | Y | Y | N | N | Y | Y | N | N | Y |
| 11. Were the participants asked to participate in the study representative of the entire population from which they were recruited? | U | U | U | U | U | U | Y | U | U | U | U | U | U | N | U | U |
| 12. Were those participants who were prepared to participate representative of the entire population from which they were recruited? | U | U | U | U | U | U | U | U | U | U | U | U | U | U | U | U |
| 12a. Was the participation rate reported? | N | N | N | N | N | NA | NA | Y | Y | N | N | N | N | N | N | N |
| 13. Were the staff, places, and facilities where the patients were treated, representative of the treatment the majority of patients receive? | Y | U | U | U | Y | Y | Y | Y | Y | U | Y | Y | Y | U | U | Y |
| 14. Was an attempt made to blind participants to the intervention they have received? | Y | Y | Y | Y | U | NA | N | Y | Y | U | NA | NA | NA | U | U | U |
| 15. Was an attempt made to blind those measuring the main outcomes of the intervention? | U | U | U | U | U | NA | U | Y | Y | N | NA | NA | NA | U | U | U |
| 16. If any of the results of the study were based on “data dredging”, was this made clear? | NA | Y | Y | Y | Y | Y | Y | Y | Y | NA | Y | NA | NA | N | NA | NA |
| 17. In trials and cohort studies, do the analyses adjust for different lengths of follow-up of patients, or in case-control studies, is the time period between the intervention and outcome the same for cases and controls? | NA | NA | NA | NA | N | NA | Y | Y | Y | NA | NA | NA | NA | NA | NA | NA |
| 18. Were the statistical tests used to assess the main outcomes appropriate? | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | N | Y | Y | Y |
| 19. Was compliance with the intervention/s reliable? | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| 20. Were the main outcome measures used accurate (valid and reliable)? | U | U | U | U | U | Y | Y | Y | Y | U | U | U | Y | U | U | U |
| 21. Were participants in different intervention groups (trials and cohort studies) or were the cases and controls (case-control studies) recruited from the same population? | NA | NA | NA | NA | Y | NA | Y | Y | Y | NA | NA | NA | NA | NA | NA | NA |
| 22. Were participants in different intervention groups (trials and cohort studies) or were the cases and controls (case-control studies) recruited over the same period of time? | Y | Y | Y | Y | Y | NA | Y | Y | Y | Y | NA | NA | NA | Y | Y | Y |
| 23. Were participants randomized to intervention groups? | N | Y | Y | Y | N | N | N | Y | Y | Y | N | Y | N | Y | Y | Y |
| 24. Was the randomized intervention assignment concealed until recruitment was complete and irrevocable? | N | U | U | U | N | N | N | Y | Y | U | N | U | N | N | N | U |
| 25. Was there adequate adjustment for confounding in the analyses from which the main findings were drawn? | N | N | Y | N | N | N | Y | Y | Y | N | N | N | N | N | N | N |
| 26. Were losses of participants to follow-up taken into account? | NA | NA | NA | NA | NA | NA | NA | Y | Y | NA | NA | NA | NA | NA | NA | NA |
| 27. Did the study have sufficient power to detect a clinically important effect where the probability value for a difference being due to chance is less than 5%? | U | U | U | U | U | U | U | Y | Y | U | U | U | U | U | U | U |
Y=yes; N=no; U=unable to determine; NA=not applicable.
~
The studies’ numbers refer to the list in Table 3.