Table 6.
Quality assessment using Down’s and Black Checklist
| Endo et al. [30] | Osada et al. [37] | Wright et al. [32] | Endo et al. [29] | Peters et al. [38] | Waaler et al. [41] | Osada et al. [43] | Perko et al. [39] | Puvi-Rajasingham et al. [33] | Puvi-Rajasingham et al. [44] | |
|---|---|---|---|---|---|---|---|---|---|---|
| Reporting | ||||||||||
| Is the hypothesis/aim/objective of the study clearly described? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Are the main outcomes to be measured clearly described in the introduction or methods section? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Are the characteristics of the patients included in the study clearly described? | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 0 |
| Are the interventions of interest clearly described? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Are the distributions of principal confounders in each group of subjects to be compared clearly described? | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| Are the main findings of the study clearly described? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Does the study provide estimates of the random variability in the data for the main outcomes? | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 |
| Have all important adverse events that may be a consequence of the intervention been reported? | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Have the characteristics of patients lost to follow-up been described | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Have actual probability values been reported for the main outcomes except where the probability value is less than 0.001? | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| External validity | ||||||||||
| Were the subjects asked to participate in the study representative of the entire population from which they were recruited? | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
| Were those subjects who were prepared to participate representative of the entire population from which they were recruited? | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
| Were the staff, places, and facilities where the patients were treated, representative of the treatment the majority of patients receive? | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
| Internal validity bias | ||||||||||
| Was an attempt made to blind study subjects to the intervention they have received? | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Was an attempt made to blind those measuring the main outcomes of the intervention? | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| If any of the results of the study were based on data dredging, was this made clear? | 1 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 0 |
| 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 case controls? | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 |
| Were the statistical tests used to assess the main outcomes appropriate? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Was compliance with the intervention/s reliable? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Were the main outcome measures used accurate (valid and reliable)? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Internal validity–confounding (selection bias) | ||||||||||
| Were the patients in different intervention groups (trials and cohort studies) or were the cases and controls (case–control studies) recruited from the same population? | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
| Were study subjects in different intervention groups (trials and cohort studies) or were the cases and controls (case–control studies) recruited over the same period of time? | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Were the study subjects randomised to intervention groups? | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Was the randomised intervention assignment concealed from both patients and health care staff until recruitment was complete and irrevocable? | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Was there adequate adjustment for confounding in the analyses from which the main findings were drawn? | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Were losses of patients to follow-up taken into account? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Power | ||||||||||
| 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%? | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Total | 11 | 12 | 19 | 12 | 12 | 11 | 12 | 12 | 16 | 14 |
| Puvi-Rajasingham et al. [34] | Duprez et al. [42] | Eriksen et al. [28] | Chauduri et al. [35] | Muller et al. [36] | Qamar et al. [40] | |
|---|---|---|---|---|---|---|
| Reporting | ||||||
| Is the hypothesis/aim/objective of the study clearly described? | 1 | 1 | 1 | 1 | 1 | 1 |
| Are the main outcomes to be measured clearly described in the introduction or methods section? | 1 | 1 | 1 | 1 | 1 | 1 |
| Are the characteristics of the patients included in the study clearly described? | 1 | 1 | 1 | 0 | 1 | 1 |
| Are the interventions of interest clearly described? | 1 | 1 | 1 | 1 | 1 | 1 |
| Are the distributions of principal confounders in each group of subjects to be compared clearly described? | 0 | 0 | 0 | 0 | 0 | 0 |
| Are the main findings of the study clearly described? | 1 | 1 | 1 | 1 | 1 | 1 |
| Does the study provide estimates of the random variability in the data for the main outcomes? | 1 | 1 | 0 | 1 | 1 | 1 |
| Have all important adverse events that may be a consequence of the intervention been reported? | 0 | 0 | 0 | 0 | 0 | 0 |
| Have the characteristics of patients lost to follow-up been described | 1 | 1 | 1 | 1 | 1 | 1 |
| Have actual probability values been reported for the main outcomes except where the probability value is less than 0.001? | 0 | 1 | 0 | 0 | 1 | 1 |
| External validity | ||||||
| Were the subjects asked to participate in the study representative of the entire population from which they were recruited? | 0 | 0 | 0 | 1 | 1 | 0 |
| Were those subjects who were prepared to participate representative of the entire population from which they were recruited? | 0 | 0 | 0 | 1 | 1 | 0 |
| Were the staff, places, and facilities where the patients were treated, representative of the treatment the majority of patients receive? | 0 | 0 | 0 | 1 | 1 | 0 |
| Internal validity bias | ||||||
| Was an attempt made to blind study subjects to the intervention they have received? | 0 | 0 | 0 | 0 | 0 | 0 |
| Was an attempt made to blind those measuring the main outcomes of the intervention? | 0 | 0 | 0 | 0 | 0 | 0 |
| If any of the results of the study were based on data dredging, was this made clear? | 1 | 0 | 0 | 1 | 0 | 0 |
| 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 case controls? | 0 | 0 | 0 | 0 | 0 | 0 |
| Were the statistical tests used to assess the main outcomes appropriate? | 1 | 1 | 1 | 1 | 1 | 1 |
| Was compliance with the intervention/s reliable? | 1 | 1 | 1 | 1 | 1 | 1 |
| Were the main outcome measures used accurate (valid and reliable)? | 1 | 1 | 1 | 1 | 1 | 1 |
| Internal validity–confounding (selection bias) | ||||||
| Were the patients in different intervention groups (trials and cohort studies) or were the cases and controls (case–control studies) recruited from the same population? | 0 | 0 | 0 | 1 | 1 | 0 |
| Were study subjects in different intervention groups (trials and cohort studies) or were the cases and controls (case–control studies) recruited over the same period of time? | 0 | 0 | 0 | 0 | 0 | 0 |
| Were the study subjects randomised to intervention groups? | 0 | 0 | 0 | 0 | 0 | 0 |
| Was the randomised intervention assignment concealed from both patients and health care staff until recruitment was complete and irrevocable? | 0 | 0 | 0 | 0 | 0 | 0 |
| Was there adequate adjustment for confounding in the analyses from which the main findings were drawn? | 0 | 0 | 0 | 0 | 0 | 0 |
| Were losses of patients to follow-up taken into account? | 1 | 1 | 1 | 1 | 1 | 1 |
| Power | ||||||
| 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%? | 0 | 0 | 0 | 0 | 0 | 0 |
| Total | 12 | 12 | 10 | 15 | 16 | 12 |