Table 1.
Criteria for evaluation adapted from Downs and Black [18]
| Criteria | |
|---|---|
| 1. | Is the hypothesis/aim/objective of the study clearly described? |
| 2. | Are the main outcomes to be measured clearly described in the Introduction or Methods section? |
| 3. | Are the characteristics of the subjects included in the study clearly described?a |
| 4. | Are the interventions of interest clearly described?b |
| 5. | Are the distributions of principal confounders in each group of subjects to be compared clearly described? |
| 6. | Are the main findings of the study clearly described? |
| 7. | Does the study provide estimates of the random variability in the data for the main outcomes? |
| 8. | Have all important adverse events that may be a consequence of the intervention been reported?b |
| 9. | Have the characteristics of subjects lost to follow-up (refusals) been described?a |
| 10. | Have 95 % confidence intervals and/or p values been reported for the main outcomes, except where the p value is less than 0.001?a |
| 11. | Were the subjects asked to participate in the study representative of the entire population from which they were recruited? |
| 12. | Were those subjects who were prepared to participate representative of the entire population from which they were recruited?b |
| 13. | Were the staff, places, and facilities where the patients were treated, representative of the treatment the majority of patients receive?b |
| 14. | Was an attempt made to blind study subjects to the intervention they have received?b |
| 15. | Was an attempt made to blind those measuring the main outcomes of the intervention?b |
| 16. | If any of the results of the study were based on “data dredging”, was this made clear? |
| 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?b |
| 18. | Were the statistical tests used to assess the main outcomes appropriate? |
| 19. | Was compliance with the intervention/s reliable?b |
| 20. | Were the main outcome measures used accurate (valid and reliable)? |
| 21. | Were the groups to be compared recruited from the same population?a |
| 22. | Were the study subjects recruited over the same period of time?a |
| 23. | Were study subjects randomised to intervention groups?b |
| 24. | Was the randomised intervention assignment concealed from both patients and health care, Staff until recruitment was complete and irrevocable?b |
| 25. | Was there adequate adjustment for confounding in the analysis from which the main findings were drawn? |
| 26. | Were losses of subjects to follow-up taken into account?a |
| 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 %? |
aQuestions adapted for longitudinal studies
bQuestions disregarded in this assessment as they did not apply to observational studies