Table 3 Details on the certainty of evidence ratings including down- and upgrading’s of the evidence according to study design

The rating of the certainty per outcome, n

811

544

256

11 (5 studies)

 High, n (%)

84 (10.4)

83 (15.3)

1 (0.4)

0

 Moderate, n (%)

199 (24.5)

151 (27.7)

45 (17.6)

3 (27.3)

 Low, n (%)

260 (32.1)

185 (34.0)

69 (27.0)

6 (54.5)

 Very low, n (%)

268 (33.0)

125 (23.0)

141 (55.0)

2 (18.2)

Total number of downgrading domains, n

1012

667

339

6

 Risk of bias, n (%)

528 (52.2)

358 (53.8)

167 (49.3)

3 (50.0)

 Imprecision, n (%)

278 (27.5)

207 (31.0)

71 (21.0)

0

 Inconsistency, n (%)

146 (14.4)

84 (12.6)

60 (17.7)

2 (33.3)

 Indirectness, n (%)

55 (5.4)

17 (2.5)

37 (10.8)

1 (16.7)

 Publication bias, n (%)

5 (0.5)

1 (0.1)

4 (1.2)

0

Upgradings, n

21

0

19

2

 Large effect, n (%)

3 (14.3)

0

1 (5.3)

2 (100.0)

 Dose–response, n (%)

10 (47.6)

0

10 (52.6)

0

 Plausible confounding, n (%)

8 (38.1)

0

8 (42.1)

0

Frequency of the rating domains

 Mean frequency, n of Downgradings domains, n / The rating of the certainty per outcome, n

1.25

1012/811

1.23

667/544

1.32

339/256

0.55

6/11

  Risk of bias, n (% of outcomes downgraded)

528 (65.1)

358 (65.8)

167 (65.2)

3 (27.3)

  Imprecision, n (% of outcomes downgraded)

278 (34.3)

207 (38.0)

71 (27.7)

0

  Inconsistency, n (% of outcomes downgraded)

146 (18.0)

84 (15.4)

60 (23.4)

2 (18.2)

  Indirectness, n (% of outcomes downgraded)

55 (6.8)

17 (3.1)

37 (14.5)

1 (9.1)

  Publication bias, n (% of outcomes downgraded)

5 (0.6)

1 (0.2)

4 (1.6)

0

 Mean frequency, n of Upgrading domains, n / The rating of the certainty per outcome, n

0.03

21/811

0.00

0/544

0.07

19/256

0.18

2/11

  Large effect, n (% of outcomes upgraded)

3 (0.4)

0

1 (0.4)

2 (18.2)

  Dose–response, n (% of outcomes upgraded)

10 (1.2)

0

10 (3.9)

0

  Plausible confounding, n (% of outcomes upgraded)

8 (1.0)

0

8 (3.1)

0