Quality assessment item	Maximum points awardable
Reporting (9 items)
Is hypothesis/aims clearly described?	1
Are the main outcomes to be measured clearly described?	1
Are the characteristics of the patients included in the study clearly described	1
Are the interventions of interest clearly described?	1
Are the distributions of principal confounders in each group of subjects to be compared clearly described?	2
Are the main findings of the study clearly described?	1
Does the study provide estimates of the random variability in the data for the main outcomes?	1
Have all important adverse events that may be a consequence of the intervention been reported?	1
Have the characteristics of patients lost to follow-up been described?	1
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?	1
External validity (3 items)
Were the subjects asked to participate in the study representative of the entire population from which they were recruited?	1
Were those subjects who were prepared to participate representative of the entire population from which they were recruited?	1
Were the staff, places, and facilities where the patients were treated, representative of the treatment the majority of patients receive?	1
Bias (7 items)
If any of the results of the study were based on “data dredging”, was this made clear?	1
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?	1
Were the statistical tests used to assess the main outcomes appropriate?	1
Was compliance with the intervention/s reliable?	1
Were the main outcome measures used accurate (valid and reliable)?	1
Confounding (6 items)
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?	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?	1
Were losses of patients to follow-up taken into account?	1
Power (1 item)
Does the study describe its calculation of power in order to demonstrate a clinically significant effect?	1
Total	23