Endoscopic retrograde cholangiopancreatography in cirrhosis - a systematic review and meta-analysis focused on adverse events

Table 4 Methodological quality of included studies using the Newcastle-Ottawa scale

Ref.	Country	Study type	Cohort/ Case-control	Yr	No. of patients	Newcastle-Ottawa Scale		Outcome
						Selection	Comparability
Navaneethan et al[5]	United States	Retrospective	Case-control	2010	3228	A	C	***
Jagtap et al[20]	India	Retrospective	Cohort	2014-2016	134	A		**
Adler et al[16]	United States	Retrospective	Cohort	2003-2014	328	A	C	***
Inamdar et al[13]	United States	Retrospective	Case-control	2009	1930	A	B	**
Gill et al[14]	Pakistan	Retrospective	Case-control	2008-2014	100	A	C	**
Churrango et al[24]	United States	Retrospective	Cohort	2008-2015	194	A	C	**
Leal et al[19]	Spain	Retrospective	Case-control	2002-2014	158	A	C	***
Zhang et al[2]	China	Retrospective	Cohort	2000-2014	77	A	C	***
Li et al[17]	China	Retrospective	Cohort	2000-2008	46	A	C	***
Ma et al[22]	China	Retrospective	Cohort	2002-2013	41	B	C	**
Artifon et al[21]	Brazil	Prospective	Case-control	Not specified	105	B	C	***
Park et al[18]	South Korea	Prospective/Retrospective	Case-control	1998-2003	41	A	C	***
Prat et al[25]	France	Retrospective	Cohort	1988-1993	52	A+	C	***
Freeman et al[23]	United States	Prospective	Case-control	Not specified	64	A	C	***
Sugiyama et al[15]	Japan	Prospective	Cohort	Not specified	7	B	C	***

A+: Excellent; A: Very good; B: Good; C: Fair.