Osteopathic manipulative treatment for nonspecific low back pain: a systematic review and meta-analysis

Table 4 Risk of bias in the included studies

	Randomisation?	Allocation concealed?	Patient blinding?	Care provider blinding?¹	Outcome assessor blinding?²	Drop-outs described + acceptable?	Free of selective outcome report?	Groups similar at baseline?	Co-intervention avoided or similar?	Compliance acceptable?	Intention-to-treat analysis?	Similar timing outcome assessment?
Study	1	2	3	4	5	6	7	8	9	10	11	12
Adorjàn-Schaumann 1999	LR	LR	UC	HR	UC	LR	LR	LR	LR	HR	LR	LR
Andersson 1999	LR	LR	HR	HR	HR	LR	LR	LR	LR	LR	HR	LR
Chown 2008	LR	LR	UC	HR	UC	LR ³	LR	LR	LR	LR	UC	LR
Cruser 2012	LR	LR	HR	HR	HR	LR	LR	LR	LR	LR	LR	LR
Gibson 1985	UC	UC	HR	HR	HR	LR	LR	HR	LR	LR	UC	LR
Gundermann 2013	LR	LR	HR	HR	HR	LR	LR	LR	LR	LR	LR	HR
Heinze 2006	LR	LR	HR	HR	HR	LR	LR	HR	LR	LR	LR	LR
Licciardone 2003	LR	LR	UC	HR	UC	UC	HR	LR	LR	UC	UC	LR
Licciardone 2009	LR	UC	HR	HR	HR	HR	LR	LR	LR	LR	LR	LR
Licciardone 2013	LR	LR	UC	HR	UC	LR	HR	LR	LR	LR	LR	LR
Mandara 2008	LR	LR	UC	HR	UC	LR	LR	UC	LR	LR	HR	LR
Recknagel 2007	LR	LR	HR	HR	HR	LR	LR	HR	LR	LR	LR	LR
Peters 2006	LR	LR	HR	HR	HR	LR	LR	LR	LR	LR	HR	LR
Schwerla 2012	LR	LR	HR	HR	HR	LR	LR	HR	LR	LR	LR	LR
Vismara 2012	LR	LR	HR	HR	HR	LR	LR	LR	LR	LR	HR	LR

¹In manual therapy studies, blinding is not possible.
²For patient-reported outcomes, a low risk of bias is only possible if there is a low risk of bias for participant blinding.
³Comparison between osteopathic manipulative treatment and physiotherapy group is low risk, but comparison between osteopathic manipulative treatment and exercise group is high risk (due to high dropout rate). This comparison was therefore excluded from the review.
Abbreviations: HR High risk of bias, LR Low risk of bias, UC Unclear.