Table 1

Participant characteristics

Topic	Trial	Authors	Surgeons	Other	Total
Stroke	FOOD	1	1	2	4
Gastro-oesophageal reflux disease	REFLUX	0	1	6	7
Abdominal aortic aneurysm	EVAR	1	2	5	8
Knee replacement	KAT	1	2	5	8
Varicose veins	REACTIV/CLaSS	3	3	5	11

CLaSS, Comparison of LAser, Surgery and foam Sclerotherapy; EVAR, EndoVascular Aneurysm Repair; FOOD, Feed Or Ordinary Diet ; KAT, Knee Arthroplasty Trial; REACTIV, Randomised and Economic Assessment of Conservative and Therapeutic Interventions for Varicose Veins .