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Table 1 Examples of unclear supporting explanations

From: Assessments of attrition bias in Cochrane systematic reviews are highly inconsistent and thus hindering trial comparability

Study number

Unclear supporting explanation

Judgment

2

All participants were accounted for

Low

12

Outcomes reported for all women randomized

Low

20

Primary outcomes were reported

Low

26

None found

Low

54

Analysed the same number of participants in both groups

Low

66

Expected outcomes reported. Response rates reduced in patients over 4 surveys

Low

80

No study protocol was available

Low

82

It appears that all participants completed the study and contributed data for each outcome at all relevant time points

Low

2

Unclear

Unclear

4

Losses to follow-up were unclear

Unclear

6

It was unclear whether or not there was attrition, or loss to follow-up at final follow-up based on the results section

Unclear

29

No information

Unclear

31

Insufficient information to permit judgment of low risk or high risk

Unclear

32

May be participants randomized who did not complete

Unclear

41

Few data available in conference abstract only

Unclear

66

Unknown

Unclear

442

High attrition (41%)

Unclear

13

Number of drop-outs reported, but no details

High

25

Not all raw data were provided

High

52

Not clear how many withdrew

High