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

Table 1 Characteristics of the 133 included RCT reports

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)
	Other^a	24 (18.1)
Nature of Control Arm	Active Control	63 (47.4)
	Placebo Control	70 (52.6)
Funding Source	External^b	123 (92.5)
	Internal/Not stated^c	10 (7.5)

^a For example, care management, patient education, radiotherapy or mixed interventions
^b For example, pharmaceutical companies, government agencies, charities etc.
^c For example, hospital department where trial took place; no additional external funding obtained

ISSN: 1745-6215