Table 1

Study characteristics by registration status

Registered, n (%)Not registered, n (%)TotalP value
140 (69.0)63 (31.0)203
Industry funding
 Yes132 (80.0)33 (20.0)165<0.001
 No8 (72.7)3 (27.2)11
 Not reported027 (100.0)27
Country
 Multinational82 (90.1)9 (9.9)91<0.001
 Europe26 (50.0)26 (50.0)78
 North America18 (64.2)10 (35.7)28
 Asia6 (23.1)20 (76.8)26
 South America2 (66.7)1 (33.3)3
 Australia (Oceania)01 (100.0)1
 Africa1 (100.0)01
 Not reported1 (100.0)01
Clinical condition
 Alzheimer’s disease40 (59.7)27 (40.3)670.045
 COPD100 (73.5)36 (26.5)136
Journal impact factor
 0–1.9994 (23.5)13 (76.5)17<0.001
 2.000–4.99986 (69.9)37 (30.1)123
 5.000–9.99917 (60.7)11 (39.3)28
 10.000–14.99914 (87.5)2 (12.5)16
 ≥15.00019 (100.0)019
 Registration stated in publication
 Yes109 (100.0)0109<0.001
 No31 (33.0)63 (67.0)94
Sample size
 0–4919 (46.3)22 (53.7)41<0.001
 50–996 (31.6)13 (68.4)19
 100–19917 (65.4)9 (34.6)26
 200–49941 (75.9)13 (24.1)54
 500–99927 (81.8)6 (18.2)33
 ≥100030 (100.0)030
  • COPD, chronic obstructive pulmonary disease.