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Table 2 Reporting of randomized controlled trials with multiple arms by trial design

From: Reporting of analyses from randomized controlled trials with multiple arms: a systematic review

 

All trials, n = 298

Trial design

  

Parallel group, n = 221

Parallel group with factorial, n = 37

Crossover (n = 40)

Reporting item

    

Study hypothesis defined

238 (79.9)

173 (78.3)

33 (89.1)

32 (80.0)

Baseline characteristics available per group

253 (84.9)

196 (88.7)

28 (75.7)

29 (72.5)

Results on outcomes available per group

250 (83.9)

190 (85.0)

27 (73.0)

33 (82.5)

Global test comparison

    

 Planned

171 (57.4)

127 (57.5)

23 (62.2)

21 (52.5)

 Reported

116 (38.9)

84 (38.0)

18 (48.7)

14 (35.0)

Pairwise test comparisons

    

 Planned

180 (60.4)

144 (65.2)

11 (29.7)

25 (62.5)

 Reported

204 (68.5)

162 (73.3)

15 (40.5)

27 (67.5)

Sample-size calculation

    

 Reported

210 (70.5)

159 (72.0)

30 (81.1)

21 (52.5)

 Taken into account in the multi-arm design

41/210 (19.5)

35/159 (22.0)

5/30 (16.7)

1/21 (4.8)

Adjustment method used to control type I error due to multiple-arm design a

118 (39.6)

89 (40.3)

10 (27.0)

19 (47.50)

Title identified the study as a multiple-arm trial

130 (43.6)

101 (45.7)

19 (51.4)

10 (25.0)

  1. a For sample-size calculation or for statistical analysis.