Table 1 Characteristics of systematic reviews published in six major medical journals from July 2012 through June 2013

Journal, n (%)

  Annals of Internal Medicine

41

16 (39)

25 (61)

  BMJ

37

13 (35)

24 (65)

  The Journal of the American Medical Association

11

4 (36)

7 (64)

  The Lancet

12

4 (33)

8 (67)

  The New England Journal of Medicine

1

0 (0)

1 (100)

  PLOS Medicine

15

4 (27)

11 (73)

Funding source, n (%)^a

  Industry

38

17 (45)

21 (55)

  NIH^b/government

81

29 (36)

52 (64)

  Other

32

11 (34)

21 (66)

  None

13

4 (31)

9 (69)

Manuscript reported PRISMA compliance

38

18 (47)

20 (53)

Number of individual studies included in review, median (range)

30 (5–639)

35 (5–639)

29 (5–379)