Table 8.

Characteristics of Randomized Clinical Trials by Presence of Avoidable Design Flaws

Characteristic	Absence of design flaw, No. (%)	Presence of design flaw, No. (%)	Total, No. (%)	P
Time of registration
2003–2013.06	15 (55.56)	66 (73.33)	81 (69.23)	0.079
2013.06–2023	12 (44.44)	24 (26.67)	36 (30.77)
Primary purpose
Treatment	25 (92.59)	74 (82.22)	99 (84.62)	0.505
Other	2 (7.41)	15 (16.67)	17 (14.53)
Prevent	0 (0.00)	1 (1.11)	1 (0.85)
Intervention
Pharmacological	19 (70.37)	63 (70.00)	82 (70.09)	0.971
Nonpharmacological	8 (29.63)	27 (30.00)	35 (29.91)
Intervention model
Crossover	2 (7.41)	17 (18.89)	19 (16.24)	0.108
Parallel	24 (88.89)	73 (81.11)	97 (82.91)
Factorial	1 (3.70)	0 (0.00)	1 (0.85)
Arm
2	21 (77.78)	73 (81.11)	94 (80.34)	0.671
3	4 (14.81)	14 (15.56)	18 (15.38)
≥4	2 (7.41)	3 (3.33)	5 (4.27)
Blinding
None or open label	3 (11.11)	31 (34.44)	34 (29.06)	0.025*
Single	2 (7.41)	10 (11.11)	12 (10.26)
Double or more	22 (81.48)	49 (54.44)	71 (60.68)
Funder type
None or  departmental	16 (59.26)	46 (51.11)	62 (52.99)	0.457
Industry or other  external	11 (40.74)	44 (48.89)	55 (47.01)
Recruitment
Single center	11 (40.74)	35 (38.89)	46 (39.32)	0.674
Multicenter	14 (51.85)	54 (60.00)	68 (58.12)
Missing	2 (7.41)	1 (1.11)	3 (2.56)
No. of participants
<350	17 (62.96)	64 (71.11)	81 (69.23)	0.421
≥350	10 (37.04)	26 (28.89)	36 (30.77)
PI region
Nonhigh SDI	8 (29.63)	17 (18.89)	25 (21.37)	0.232
High SDI	19 (70.37)	73 (81.11)	92 (78.63)
PI region
<90	21 (77.78)	79 (87.78)	100 (85.47)	0.218
≥90	6 (22.22)	11 (12.22)	17 (14.53)
PI region
High income	21 (77.78)	75 (83.33)	96 (82.05)	0.570
Nonhigh income	6 (22.22)	15 (16.67)	21 (17.95)
PI region
North America	8 (29.63)	34 (37.78)	42 (35.90)	0.693
Europe	8 (29.63)	21 (23.33)	29 (24.79)
Other	11 (40.74)	35 (38.89)	46 (39.32)

^*P < 0.05