Skip to main content

Table 1 Characteristics of the 133 included RCT reports

From: A review of reporting of participant recruitment and retention in RCTs in six major journals

Trial characteristic   Number of Included RCT Reports (%)
Journal NEJM 39 (29.3)
  Lancet 31 (23.3)
  JAMA 25 (18.8)
  BMJ 15 (11.3)
  Annals of Internal Medicine 13 (9.8)
  Annals of Surgery 10 (7.5)
Sample Size <200 33 (24.8)
  200–449 37 (27.8)
  450–749 31 (23.3)
  750+ 32 (24.1)
Centres Multiple 95 (71.4)
  Single 38 (28.6)
Study Design Parallel 125 (94.0)
  Factorial 5 (3.8)
  Crossover 3 (2.3)
Number of Arms Two 103 (77.4)
  Three 14 (10.5)
  Four 12 (9.0)
  Five 2 (1.5)
  Six 2 (1.5)
Interventions Drug 68 (51.1)
  Surgery 21 (15.8)
  Allied/Complementary Medicine 20 (15.0)
  Othera 24 (18.1)
Nature of Control Arm Active Control 63 (47.4)
  Placebo Control 70 (52.6)
Funding Source Externalb 123 (92.5)
  Internal/Not statedc 10 (7.5)
  1. a For example, care management, patient education, radiotherapy or mixed interventions
  2. b For example, pharmaceutical companies, government agencies, charities etc.
  3. c For example, hospital department where trial took place; no additional external funding obtained
\