Table 7.

Risk of bias ‐ studies assessed as low risk of bias

Review	Number of studies in assessment	Selection bias		Performance bias	Detection bias	Attrition bias	Reporting bias	Other bias
		Random sequence generation (studies)	Allocation concealment (studies)	Blinding of participants and personnel (studies)	Blinding of outcome assessment (studies)	Incomplete outcome data (studies)	Selective reporting (studies)	Sample size	Other biases (studies)
Bartels 2007	6	Not reported	3	Not reported	2	3	Not reported	2, n > 100 per arm	‐
Bidonde 2014	9	5	3	2	8	8	5	1, n > 50 per arm	7
Boldt 2014	3	1	1	0	1	2	3	0	1
Brown 2010	1	0	0	0	0	1	1	1, n > 50 per arm	‐
Busch 2007	34	17	10	8	20	Unclear	32	5, n > 50 per arm	‐
Busch 2013	5	4	2	1	2	5	3	0, n > 50 per arm	‐
Cramp 2013	7	5	2	0	Not reported	6	4		1
Fransen 2014	10	8	7	0	0	7	4	1, n > 50 per arm	7
Fransen 2015	54	40	22	3	4	29	10	5, total n > 200
Gross 2015a	16	8	8	1	0	11	0	0	11
Han 2004	4	2	0	0	0	0	Not reported	0
Hayden 2005	43	27	22	Not reported	12	29	Not reported	10, total n > 100 + 5, total n > 200	‐
Hurkmans 2009	8	8	1	‐	4	5	‐	1, total n > 200	1
Koopman 2015	2	1	0	0	0	0	0	0	1
Lane 2014	30	16	14	30	7	19	29	3, total n > 100
Lauret 2014	5	4	2	5	3	4	5	1, total n > 100	4
Regnaux 2015	1	1	0	0	1	0	0	1, total n > 100	1
Saragiotto 2016	7	5	4	1	1	2	7	1, total n > 100 + 1, total n > 200	7
Silva 2010	0	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a
van der Heijden 2015	10	8	6	0	0	6	9	2, total n > 100	10
Yamato 2015	9	5	5	2	7	7	9	0	9
Studies with low risk of bias (number)	264	165	112	53	72	144	121	total n > 100: 26 total n > 200: 15 total n > 400: 0	71
Studies with low risk of bias (percentage)	‐	63%	42%	20%	27%	55%	46%	total n > 100: 10% total n > 200: 6% total n > 400: 0%	27%

n: number of participants, n/a: not applicable.