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Table 2 Characteristics of included articles

From: Risk of bias in observational studies using routinely collected data of comparative effectiveness research: a meta-research study

  N = 77 (%)
Name of journal
 - NEJM 3 (4)
 - The Lancet 2 (3)
 - JAMA 13 (17)
 - Annals of Internal Medicine 9 (11)
 - BMJ 14 (18)
 - PLoS Medicine 8 (11)
 - Circulation 7 (9)
 - European Heart Journal 4 (5)
 - Journal of the American College of Cardiology 15 (19)
Location of corresponding authors
 - North America 40 (52)
 - Europe 25 (32)
 - Asia 10 (13)
 - North American and Europe 1 (1)
 - International 1 (1)
Study design
 - Cohort study 67 (87)
 - Not clearly reported 10 (13)
Treatment evaluated
 - Pharmacological treatment 53 (69)
 - Non-pharmacological treatment 23 (30)
 - Both 1 (1)
Comparator
 - Active comparator 49 (63)
 - Usual care 17 (22)
 - No treatment 11 (14)
Median sample size [min–max] 24,000 [9100–80,000]
Data sourcea
 - Registry 34 (44)
 - Electronic health record 17 (22)
 - Health administration data 14 (18)
 - Health insurance claims data 20 (26)
 - Others 11 (14)
Funding source
 - Not for profit 43 (56)
 - For profit 7 (9)
 - Both 12 (16)
 - No funding 5 (6)
 - Unclear 10 (13)
Research transparency practices
 - Using a reporting guideline 7 (9)
 - Code and algorithm used to classify exposures provided in supplementary documents 57 (74)
 - Code and algorithm used to classify outcomes provided in supplementary documents 60 (78)
 - A statement to provide data upon request 10 (13)
  1. aOne study might have more than one type of data sources