Table 1. Characteristics and journal of publication of clinical studies.

	Observational studies (N = 86)	Randomized controlled trials (N = 85)
Journal of publication, N (%)
Annals of Internal Medicine	8 (9)	3 (4)
BMJ	24 (28)	13 (15)
JAMA	10 (12)	11 (13)
JAMA Internal Medicine	13 (15)	3 (4)
Lancet	8 (9)	25 (29)
NEJM	16 (19)	29 (34)
PLOS Medicine	7 (8)	1 (1)
“Hard” primary outcome, N (%)	77 (90)	38 (45)
Sample size > 1000, N (%)	68 (79)	36 (42)
Study duration, y median (95% CI)	3.0 (0.9–5.0)	1.0 (0.5–1.0)
Statistically significant effect on primary outcome, N (%)	65 (76)	54 (64)