Registration of phase 3 crossover trials on ClinicalTrials.gov

Table 1 Registration of key features for randomized crossover design (N = 124)

Characteristics^a	n	(%)
Protocol section
Crossover sequence
AB\|BA	85	(68)
ABC\|ACB\|BCA\|BAC\|CAB\|CBA	16	(13)
AAB\|ABA\|BAA	2	(2)
ABC\|BAC\|CAB	2	(2)
ABA\|BAB	1	(< 1)
ABCD\|BDAC\|DCBA\|CADB	2	(2)
Others	12	(10)
No sequences registered	4	(3)
“Arms” and “Assigned Interventions”
By sequence	73	(59)
By intervention	49	(39)
Others	2	(2)
Results section
“Participant Flow”
Provided sufficient information to understand the participant flow^b	97	(78)
By sequence and used separate tables/periods	89
By sequence and used “milestones” rows within one table	5
By sequence and used one table, without missing data	2
By intervention and used separate tables	1
Provided insufficient information to understand the participant flow	27	(22)
By sequence and by total	18
By total only	4
Others	5
“Baseline Characteristics”
By sequence	55	(44)
By total only	65	(52)
Others	4	(3)
“Outcome Measures”—first primary outcome^b
By sequence	6	(5)
By sequence and by period	2	(2)
By intervention	105	(84)
By total only	3	(2)
Others	8	(6)
“Serious Adverse Events”
By sequence	8	(6)
By total only	4	(3)
By intervention only	99	(80)
By intervention and period	3	(2)
Others	5	(4)
No adverse events reported	5	(4)

^aAssessment was based on data presented on ClinicalTrials.gov on August 6, 2019
^bRecords that provided sufficient information to understand the participant flow may (1) use separate tables for each treatment period (e.g., NCT00432744); (2) use “milestone” rows for each period within one table (e.g., NCT00432835); (3) use one table when there is no missing data (e.g., NCT01808755); or (4) use separate tables for each treatment period by intervention (e.g., NCT01323660)

ISSN: 1745-6215