() Distribution of principal confounders in each group
0
0
0
0
0
0
0
0
2
() Main findings
1
1
1
1
1
1
1
1
1
() Estimates of random variability for main outcomes
1
1
1
1
1
1
1
1
1
() All important adverse events that may be a consequence of intervention
0
0
0
1
1
0
0
1
0
() Characteristics of patients lost to follow-up
1
1
1
1
1
1
1
0
0
(0) Actual probability values for main outcomes
1
1
1
1
1
1
1
1
1
External validity
(1) Were invitees representative of the population from which they were recruited?
0
0
0
1
0
0
0
0
0
(2) Were subjects who were prepared to participate representative of the population from which recruited?
0
0
0
1
0
1
0
0
0
() Were the staff, places, and facilities representative of the treatment that the majority of subjects received?
0
0
0
1
1
1
0
0
0
Internal validity
(4) Was an attempt made to blind subjects to the intervention they received?
0
0
0
0
0
0
0
0
0
(5) Was an attempt made to blind those measuring main outcomes of the intervention?
0
0
0
1
0
0
0
0
0
(6) If any results were based on “data dredging,” was this made clear?
0
0
0
1
1
1
0
1
1
(7) In trials and cohort studies, did analyses adjust for length of follow-up? Or, in case-control studies, was the period between intervention and outcome the same for cases and controls?
1
1
1
1
1
1
1
1
0
(8) Were appropriate statistical tests used to assess the main outcomes?
1
1
1
1
1
1
1
0
1
(9) Was compliance with the intervention reliable?
1
1
1
1
1
1
1
1
1
() Were main outcome measures reliable and valid?
1
1
1
1
1
1
1
0
1
Internal validity-confounding (selection bias)
() For trials and cohort studies, were patients in different intervention groups? For case-control studies, were cases and controls recruited from the same population?
1
1
1
1
1
1
1
0
0
() For trials and cohort studies, were subjects in different intervention groups? For case-control studies, were cases and controls recruited over same period of time?
1
1
1
1
1
0
1
0
0
() Were subjects randomized to intervention groups?
1
1
1
1
0
0
1
0
0
() Was the randomized intervention assignment concealed from both patients and staff until recruitment was complete? Was it irrevocable?
1
1
1
1
0
0
1
0
0
() Was there adequate adjustment for confounding in analyses from which main findings were drawn?
0
0
0
0
0
0
0
0
0
() Were losses of subjects to follow-up taken into account?
1
1
1
1
1
0
1
0
0
Power
() Was there sufficient power to detect a clinically important effect when ?
0
0
0
0
0
0
0
0
0
Total score (maximum 32)
17
17
17
23
18
16
17
11
13
A score of 23 or higher indicates good-quality article with low risk of bias. A score between 22 and 13 indicates medium-quality article with moderate risk of bias. A score of 12 or lower represents a poor-quality article with high risk of bias [25].
