Table 1.

Summary characteristics of the sample of trials (n = 75)

Characteristic	Category	n (%)
Study type	Efficacy/superiority	70 (93.3)
	Equivalence	4 (5.3)
	Noninferiority	1 (1.3)
Trial design	Parallel	54 (72.0)
	Cluster	14 (18.7)
	Crossover	3 (4.0)
	Split body	2 (2.7)
	Factorial	0 (0)
	Other	2 (2.7)
Intervention class	Drug	18 (24.0)
	Communication, organizational, or educational	12 (16.0)
	Rehabilitation or psychosocial	12 (16.0)
	Device	11 (14.7)
	Alternative therapeutic	7 (9.3)
	Prevention or screening	6 (8.0)
	Vaccine	3 (4.0)
	Surgery or radiotherapy	2 (2.7)
	Other	4 (5.3)
Control type	Active intervention	36 (48.0)
	No intervention	15 (20.0)
	Placebo	15 (20.0)
	Wait-list control	9 (12.0)
Primary outcome category	Physiological	22 (29.3)
	Behavioral	16 (21.3)
	Psychological	13 (17.3)
	Biomarker	12 (16.0)
	Techniques or training	5 (6.7)
	Quality of life	2 (2.7)
	Pain	1 (1.3)
	Other	4 (5.3)