Table 2

Association between characteristics of articles and statistically significant results or conclusions that favor the test drug: Univariate logistic regression (n = 137).

Results Favor Test Drug

Conclusions Favor Test Drug


Characteristic

Category

Favorable n/Total n (%)

OR

(95% CI)

P

Favorable n/Total n (%)

OR

(95% CI)

P


Trial registration before publication

No

44/83 (53)

1.00

55/83 (66)

1.00


Yes

36/54 (67)

1.77 (0.87-3.61)

0.115

43/54 (80)

1.99 (0.89-4.45)

0.093


Year of publication

1996-2002

16/29 (55)

1.00

21/29 (72)

1.00


2003-2004

27/40 (68)

1.69 (0.63-4.53)

0.299

30/40 (75)

1.14 (0.39-3.38)

0.809


2005-2006

18/33 (55)

0.98 (0.36-2.66)

0.961

20/33 (61)

0.59 (0.20-1.71)

0.328


2007-2008

19/35 (54)

0.97 (0.36-2.59)

0.943

27/35 (77)

1.29 (0.41-4.00)

0.664


Impact Factor*

Quartile 1 (1.55-4.44)

15/32 (47)

1.00

19/32 (59)

1.00


Quartile 2 (4.45-10.44)

19/33 (58)

1.54 (0.58-4.10)

0.389

22/33 (67)

1.37 (0.50-3.76)

0.543


Quartile 3 (10.45-17.15)

20/35 (57)

1.51 (0.58-3.96)

0.402

26/35(74)

1.98 (0.70-5.57)

0.197


Quartile 4 (17.16-52.59)

21/27 (78)

3.97 (1.27-12.43)

0.018

24/27 (89)

5.47 (1.36-22.01)

0.017


Blinding

Stringent

18/36 (50)

1.00

25/36 (69)

1.00


Not stringent

62/101 (61)

1.59 (0.74-3.42)

0.236

73/101 (72)

1.15 (0.50-2.64)

0.747


Sample Size

Quartile 1 (6-122)

10/34 (29)

1.00

19/34 (56)

1.00


Quartile 2 (123-352)

22/34 (65)

4.40 (1.59-12.19)

0.004

24/34 (71)

1.90 (0.70-5.16)

0.211


Quartile 3 (353-772)

22/35 (63)

4.06 (1.48-11.12)

0.006

26/35 (74)

2.28 (0.83-6.30)

0.112


Quartile 4 (773-8010)

26/34 (76)

7.8 (2.64-23.03)

<0.001

29/34 (85)

4.58 (1.43-14.69)

0.011


Primary efficacy outcome

Survival

17/30 (57)

1.00

21/30 (70)

1.00


Surrogate

63/107 (59)

1.10 (0.48-2.48)

0.828

77/107 (72)

1.10 (0.45-2.67)

0.833


Comparison group

Active comparator

35/65 (54)

1.00

45/65 (69)

1.00


Placebo

45/72 (63)

0.70 (0.35-1.39)

0.306

53/72 (74)

0.81 (0.38-1.70)

0.571


Sponsored

No

14/28 (50)

1.00

15/28 (54)

1.00


Yes

66/109 (61)

1.54 (0.67-3.54)

0.314

83/109 (76)

2.77 (1.17-6.56)

0.021


*Only 127 articles were published in journals with a corresponding impact factor.

Rasmussen et al. Trials 2009 10:116   doi:10.1186/1745-6215-10-116

Open Data