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Table 1 Characteristics of the included articles

From: Empirical evidence for outcome reporting bias in randomized clinical trials of acupuncture: comparison of registered records and subsequent publications

Item Total Western countries Eastern countries
n (%) = 96 n (%) = 72 n (%) = 24
Study registration    
After the trial began 76 (79.2) 58 (80.6) 18 (75.0)
Before the trial began 20 (20.8) 14 (19.4) 6 (25.0)
Study design    
Parallel 92 (95.8) 68 (94.4) 24 (100.0)
Crossover 4 (4.2) 4 (5.6) 0 (0.0)
Study center    
Single 55 (57.3) 40 (55.6) 15 (62.5)
Multiple 41 (42.7) 32 (44.4) 9 (37.5)
Number of arms    
Two 59 (61.5) 46 (63.9) 13 (54.2)
Three 29 (30.2) 22 (30.6) 7 (29.2)
Four 8 (8.3) 4 (5.5) 4 (16.7)
Funding source    
No funding 14 (14.6) 13 (18.1) 1 (4.2)
University 37 (38.5) 25 (34.7) 12 (50.0)
Hospital 13 (13.5) 7 (9.7) 6 (25.0)
Government 27 (28.1) 23 (31.9) 4 (16.7)
Private non-profit 1 (1.0) 1 (1.4) 0 (0.0)
Other source 4 (4.2) 3 (4.2) 1 (4.2)
Type of acupuncture    
Manual acupuncture 80 (83.3) 64 (88.9) 16 (66.7)
Electro-acupuncture 16 (16.7) 8 (11.1) 8 (33.3)
Intervention    
Acupuncture used alone 70 (72.9) 51 (70.8) 19 (79.2)
Acupuncture combined with other interventions* 26 (27.1) 21 (29.2) 5 (20.8)
Control†    
Placebo/sham-acupuncture# 51 (53.1) 37 (51.4) 14 (58.3)
Western medicine 25 (26.0) 18 (25.0) 7 (29.2)
No intervention 9 (9.4) 7 (9.7) 2 (8.3)
Non-pharmaceutical interventions 9 (9.4) 9 (12.5) 0 (0.0)
Conventional therapy 7 (7.3) 7 (9.7) 0 (0.0)
Acupuncture 6 (6.3) 4 (5.6) 2 (8.3)
Waiting list 4 (4.2) 3 (4.2) 1 (4.2)
Chinese herbal medicine 1 (1.0) 0 (0.0) 1 (4.2)
Specified primary outcome 71 (74.0) 50 (69.4) 21 (87.5)
Specified secondary outcome 60 (62.5) 42 (58.3) 18 (75.0)
Safety come 38 (39.6) 24 (33.3) 12 (50.0)
Health-economic outcome 5 (5.2) 5 (6.9) 0 (0.0)
Random sequence generation    
Random number table 4 (4.2) 4 (5.6) 0 (0.0)
Computer random number generator 69 (71.9) 46 (63.9) 23 (95.8)
Minimization 2 (2.1) 2 (2.8) 0 (0.0)
Not reported 21 (21.9) 20 (27.8) 1 (4.2)
Allocation concealment    
Opaque sealed envelope 23 (24.0) 19 (26.4) 4 (16.7)
Central allocation 28 (29.2) 24 (33.3) 4 (16.7)
Sealed/opaque envelope 7 (7.3) 5 (7.0) 2 (8.3)
Not reported 38 (39.6) 24 (33.3) 14 (58.3)
Blinding    
Single-blinded 37 (38.5) 26 (36.1) 11 (45.8)
 Blinding to participants 21 (21.9) 16 (22.2) 5 (20.8)
 Blinding to personnel 3 (3.1) 2 (2.8) 1 (4.2)
 Blinding to outcome assessor 13 (13.5) 8 (11.1) 5 (20.8)
Double-blinded 28 (29.2) 19 (26.4) 9 (37.5)
 Blinding to participants and personnel 10 (10.4) 9 (12.5) 1 (4.2)
 Blinding to participants and outcome assessors 18 (18.8) 10 (13.9) 8 (33.3)
 Blinding to personnel and outcome assessors 0 (0.0) 0 (0.0) 0 (0.0)
Triple-blinded 4 (4.2) 3 (4.2) 1 (4.2)
Open 15 (15.6) 11 (15.3) 4 (16.7)
Not reported 12 (12.5) 11 (15.3) 1 (4.2)
Incomplete outcome reporting 33 (34.4) 28 (38.9) 5 (20.8)
Sample size estimation 34 (35.4) 22 (30.6) 12 (50.0)
Explicit inclusion criteria 94 (97.9) 71 (98.6) 23 (95.8)
Explicit exclusion criteria 82 (85.4) 60 (83.3) 22 (91.7)
  1. Note: *Other interventions included western medicine in 18 articles, conventional therapy in 2 articles, non-pharmaceutical interventions in 4 articles, Chinese herbal medicine in 1 article and placebo drug in 1 article.
  2. †Thirty-seven (38.5%) articles reported three or four arms in one study.
  3. #Placebo acupuncture was conducted by using Streitberger placebo needles, which have a blunt tip. The needle retracted inside its handle when its tip touched the skin rather than penetrating the skin. Sham-acupuncture refers to nonspecific points, mock acupuncture/electro-acupuncture, mock transcutaneous electrical nerve stimulation, shallow needling and minimal acupuncture