Table 2

Simple logistic regression to compare aspects of trial design, conduct and analysis by types of intervention, time before and after CONSORT (2001) and impact of journal

Drug, % (n)

Non-drug, % (n)

Odds ratio (95% CI)(P-value)

From 2001, % (n)

Before 2001,% (n)

Odds ratio (95% CI) (P value)

Odds ratio (95% CI) (P value) per increase of 1 unit in impact factor


Number of trials

70

91

-

72

67

-

161

Reporting of between- group comparisons

90% (63)

90% (82)

0.98 (0.35 to 2.80) (0.98)

96% (69)

91% (61)

2.26 (0.54 to 9.44) (0.26)

1.03 (0.97 to 1.11) (0.32)

Primary outcome reported

47% (33)

20% (18)

4.06 (2.02 to 8.14) (< 0.001)

53% (38)

21% (14)

4.23 (2.00 to 8.95) (< 0.001)

1.05 (1.02 to 1.09) (0.001)

Primary outcome is only one measure

31% (22)

13% (12)

3.02 (1.37 to 6.65) (0.006)

36% (26)

12% (8)

4.17 (1.73 to 10.06) (0.001)

1.05 (1.02 to 1.08) (0.002)

No statistical comparison of baseline characteristics

79% (55)

60% (55)

2.40 (1.18 to 4.88) (0.015)

68% (49)

70% (47)

0.91 (0.44 to 1.86) (0.79)

1.03 (1.00 to 1.08) (0.089)

Reporting of handling of missing data

21% (15)

14% (13)

1.63 (0.72 to 3.71) (0.24)

26% (19)

13% (9)

2.31 (0.96 to 5.55) (0.06)

1.04 (1.01 to 1.07) (0.021)

Intention-to-treat analysis reported

53% (37)

33% (30)

2.28 (1.20 to 4.33) (0.01)

53% (38)

39% (26)

1.76 (0.90 to 3.46) (0.10)

1.03 (1.00 to 1.06) (0.047)

Reporting of P values and 9% CI

30% (21)

19% (17)

1.87 (0.89 to 3.89) (0.10)

32% (23)

22% (15)

1.63 (0.76 to 3.47) (0.21)

1.07 (1.04 to 1.11) (< 0.001)


Vollenweider et al. BMC Medicine 2011 9:73   doi:10.1186/1741-7015-9-73

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