Table 2.

Characteristics of closed cardiovascular interventional trials – 2005–2015: proportion of terminated trials (% terminated) and proportion of trials terminated because of lack of accrual (% poor) by study characteristics

		N	% Terminated	p Value‡	% Poor	p Value‡
Year	2006–2007	1078	7.0	<0.001	42.3	<0.001
	2008–2009	1893	6.6		43.0
	2010–2011	1955	6.0		43.3
	2012–2013	1596	4.9		32.8
	2014–2015	624	4.2		44.2
Facility location*	Africa	32	3.2	<0.001	100.0	<0.001
	Americas	3769	14.0		46.3
	Americas Asia Europe	129	13.2		17.6
	Americas Asia Europe Oceania	89	7.9		14.3
	Americas Europe	256	18.0		34.7
	Asia	1079	5.6		33.3
	Europe	2454	9.6		40.4
	Oceania	71	18.3		30.8
	Other	374	4.2		50.8
	Missing	647	5.9		23.7
Phase	Phase 0	81	9.9	<0.001	32.9	0.012
	Phase 1	736	11.3		29.8
	Phase 1/Phase 2	415	15.1		36.5
	Phase 2	1542	11.7		44.4
	Phase 2/Phase 3	231	13.2		36.9
	Phase 3	1419	11.0		51.5
	Phase 4	2997	8.2		46.6
	NA	1479	8.6		14.3
Intervention type	Behavioural	603	4.5	<0.001	1.8	<0.001
	Biological	294	10.2		33.3
	Device	1679	11.9		42.7
	Dietary supplement	266	5.3		50.0
	Drug	4309	13.4		39.8
	Genetic	26	7.7		0.0
	Procedure	44	13.6		45.1
	Radiation	784	10.5		83.3
	Other	895	5.4		47.9
No of arms	1	2474	11.2	0.004	42.0	<0.001
	2	4725	11.7		43.5
	>2	1466	8.5		29.8
	Missing	235	13.6		34.4
Primary purpose	Basic science	250	4.8	<0.001	25.0	0.002
	Diagnostic	491	11.0		50.0
	Health services research	197	4.1		37.5
	Prevention	1008	9.5		37.5
	Screening	46	4.3		0.0
	Supportive care	280	10.3		75.0
	Treatment	6264	12.1		39.7
	Missing	364	8.0		48.3
Allocation	Non-randomised	1052	11.0	0.986	31.0	0.155
	Randomised	6039	11.0		41.9
	Missing	1809	11.2		44.1
Endpoint classification	Bioavailability	18	5.6	<0.001	0.0	0.155
	Bioequivalence	38	7.9		66.7
	Efficacy	2668	10.7		47.2
	Pharmacodynamics	121	11.6		35.7
	Pharmacokinetics	124	4.0		0.0
	Pharmacokinetics/Dynamics	111	12.6		28.6
	Safety	625	9.1		36.8
	Safety/Efficacy	3811	12.8		37.2
	Missing	1384	8.5		47.5
Masking	Double-blind	2775	12.6	<0.001	36.7	0.119
	Open-label	4798	11.2		43.1
	Single-blind	1287	7.1		46.2
	Missing	40	15.0		33.3
Intervention model	Crossover	713	7.4	0.009	39.6	0.148
	Factorial	156	8.3		38.5
	Parallel	5246	11.4		41.5
	Single group	2727	11.4		40.8
	Missing	58	15.5		33.3
No of enrolled	(0, 100]	5521	14.0	<0.001	45.3	<0.001
	(100, 1000]	2832	6.3		27.4
	(1000, 20 000]	467	5.6		10.7
	>20 000	53	3.8		0.0
	Missing	27	19.2		40.0
No of facilities (per study)	1	4934	10.3	<0.001	44.4	<0.001
	(1, 10]	1876	14.4		44.1
	(10, 50]	1047	11.5		35.0
	(50, 100]	204	14.2		17.2
	>100	191	9.4		16.7
	Missing	648	5.9		23.7
No of conditions (per study)	1	6703	11.8	0.068	41.3	0.228
	2	1584	8.2		44.0
	>2	613	13.8		32.9
Conditions†	Acute coronary syndrome	205	12.2	-	48.3	-
	Atrial fibrillation	380	13.4		37.2
	Cardiovascular diseases	481	5.4		34.6
	Coronary artery disease	609	8.7		50.9
	Coronary disease	341	10.0		32.3
	Heart failure	644	13.8		53.9
	Hypertension	901	10.2		29.3
	Multiple myeloma	620	15.8		42.9
	Myocardial infarction	216	9.7		38.2
	Myocardial ischaemia	414	10.9		20.0
	Stroke	477	10.9		34.6
Overall		8900	11.1		41.1

*Facility location describes the study-level location of enrolling sites. It results in a single continent for single-centre trials and multicentre multinational trials and in a combination of continents for intercontinental trials.

†The number of MeSH conditions sums to 13 501 across the 8900 closed trials. Only the conditions exceeding an absolute frequency of 200 are listed.

‡χ² or Fisher test p values.