Item	Score
1	Is the hypothesis/aim/objective of the study clearly described?	yes=1; no=0
2	Are the main outcomes to be measured clearly described in the Introduction or Methods section?	yes=1; no=0
3	Are the characteristics of the patients included in the study clearly described?	yes=1; no=0
4	* Are the interventions of interest clearly described?	yes=1; no=0
5	Are the distributions of principal confounders in each group of subjects to be compared clearly described?	yes=2; partially=1; no=0
6	Are the main findings of the study clearly described?	yes=1; no=0
7	Does the study provide estimates of the random variability in the data for the main outcomes?	yes=1; no=0
8	* Have all important adverse events that may be a consequence of the intervention been reported?	yes=1; no=0
9	Have the characteristics of patients lost to follow-up been described?	yes=1; no=0
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?	yes=1; no=0
11	Were the subjects asked to participate in the study representative of the entire population from which they were recruited?	yes=1; no=0
12	Were those subjects who were prepared to participate representative of the entire population from which they were recruited?	yes=1; no=0
13	Were the staff, places, and facilities where the patients were treated, representative of the treatment the majority of patients receive?	yes=1; no=0
14	* Was an attempt made to blind study subjects to the intervention they have received?	yes=1; no=0
15	Was an attempt made to blind those measuring the main outcomes of the intervention?	yes=1; no=0
16	If any of the results of the study were based on “data dredging”, was this made clear?	yes=1; no=0
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?	yes=1; no=0
18	Were the statistical tests used to assess the main outcomes appropriate?	yes=1; no=0
19	* Was compliance with the intervention/s reliable?	yes=1; no=0
20	Were the main outcome measures used accurate (valid and reliable)?	yes=1; no=0
21	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?	yes=1; no=0
22	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?	yes=1; no=0
23	* Were study subjects randomized to intervention groups?	yes=1; no=0
24	* Was the randomized intervention assignment concealed from both patients and health care staff until recruitment was complete and irrevocable?	yes=1; no=0
25	Was there adequate adjustment for confounding in the analyses from which the main findings were drawn?	yes=1; no=0
26	Were losses of patients to follow-up taken into account?	yes=1; no=0
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%?	Size of smallest intervention group: <n1=0; n1-n2=1; n3-n4=2; n5-n6=3; n7-n8=4; n8+=5

Items 1–10 = reporting, 11–13 = external validity, 14–20 = internal validity (bias), 21–26 = internal validity (confounding) and 27 = power.

^*not applicable to observational studies.