TABLE 5

Characteristics of Published and Unpublished RCTs 24 and 36 Months After Trial Completion

Published at 24 mo (n = 262), n (%)Unpublished at 24 mo (n = 193), n (%)PPublished at 36 moa (= 354), n (%)Unpublished at 36 moa (n = 95), n (%)P
Intervention.01.11
 Behavioral34 (13.0)13 (6.7)41 (11.6)5 (5.3)
 Drug/biologic159 (60.7)145 (75.1)226 (63.8)73 (76.8)
 Device/procedure24 (9.2)8 (4.2)29 (8.2)3 (3.2)
 Dietary supplement23 (8.8)14 (7.3)30 (8.5)7 (7.4)
 Other22 (8.4)13 (6.7)28 (7.9)7 (7.4)
Age of study participants.60.64
 Preterm, newborn, and infant67 (25.6)52 (26.9)87 (24.6)31 (32.6)
 Toddler and preschool64 (24.4)37 (19.2)80 (22.6)19 (20.0)
 School age34 (13.0)23 (11.9)46 (13.0)11 (11.6)
 Adolescent23 (8.8)23 (11.9)37 (10.5)9 (9.5)
 Mixed ages74 (28.2)58 (30.1)104 (29.4)25 (26.3)
Primary funding source<.001<.001
 Academic institution130 (49.6)58 (30.1)164 (46.3)22 (23.2)
 Industry110 (42.0)121 (62.7)162 (45.8)66 (69.5)
 Other22 (8.4)14 (7.3)28 (7.9)7 (7.4)
Trial phaseb.16.06
 Phase 114 (5.3)12 (6.2)18 (5.1)7 (7.4)
 Phase 253 (20.2)36 (18.7)67 (18.9)20 (21.1)
 Phase 381 (30.9)78 (40.4)120 (33.9)38 (40.0)
 Phase 435 (13.4)26 (13.5)44 (12.4)16 (16.8)
 Unknown79 (30.2)41 (21.2)105 (29.7)14 (3.1)
Masking.29.19
 Open label94 (35.9)61 (31.6)124 (35.0)29 (30.5)
 Single blind42 (16.0)25 (13.0)56 (15.8)10 (10.5)
 Double blind126 (48.1)107 (55.4)174 (49.2)56 (59.0)
Actual sample size.07.64
 <100 participants109 (41.6)60 (31.1)134 (37.9)32 (33.7)
 100–499 participants96 (36.6)85 (44.0)138 (39.0)42 (44.2)
 >500 participants57 (21.8)48 (24.9)82 (23.2)21 (22.1)
  • a Six trials were excluded from this analysis because 36 mo had not elapsed between completion date and time that publication search was conducted.

  • b Phase 0 trials (n = 5) were included as Phase 1. Trials described as phase 1/2 (n = 15) were categorized as phase 2, and trials described as phase 2/3 (n = 15) were categorized as phase 3.