Table 3 Risk assessment for bias for the clinical studies

Pons 1995

n

py

pn

pn

n

py

n

moderate

Weiler 1995

py

py

n

n

n

n

n

moderate

Roeggla 1996

n

n

n

n

n

n

n

moderate

Lund 2003

pn

py

n

n

n

py

pn

moderate

Adir 2004

y

y

n

y

n

y

pn

critical

Biswas 2004

n

n

n

n

n

n

n

moderate

Shuppak 2004

y

y

n

n

n

py

py

serious

Wilmshurst 2004

n

y

n

n

y

n

n

serious

Deady 2006

n

n

n

n

n

n

n

moderate

Beinhart 2007

n

n

n

n

n

n

n

moderate

Wenger 2007

n

n

n

n

n

n

n

moderate

Noti 2009

n

n

n

n

n

n

n

moderate

Carter 2011

n

n

n

n

n

n

n

moderate

Ma 2013

n

py

py

pn

n

y

py

critical

North 2013

n

n

n

n

py

py

n

moderate

Casey 2014

n

n

n

n

n

n

n

moderate

Peacher 2015

pn

y

py

n

py

py

pn

critical

Yamamashi 2015

y

y

py

py

py

py

py

critical

Beale 2016

n

y

pn

py

pn

py

pn

serious

North 2013