Table 3 Specific quality threshold for sensitivity analysis used for different tools

Wong, 2013 [11]

Chorti et al. criteria: The maximum score of the checklist is 26; 50% of maximum score is cut-off for high-quality study

Grant, 2016 [12]

Jadad: high risk of bias Jadad score < 4

Johnson, 2007 [13]

Jadad: limiting the analysis to those studies with a Jadad score of at least 4

Raiman, 2016 [14]

Jadad: removing high bias studies (Jadad score < 3)

Hamilton, 2011 [15]

Jadad: score 3 classified as a higher quality study

Hauser, 2011 [16]

Jadad: studies with a low (1 to 2) and moderate (3 to 5) Jadad score

Toner, 2017 [17]

Jadad: high-quality trials only (Jadad scale score, 4 to 5).

Aya 2013 [18]

Jadad: score >3 classified as a higher quality study

Morrison, 2013 [19]

Jadad: studies with low quality (Jadad score ≤ 3) vs studies with high quality (Jadad score >3)

Wang, 2009 [20]

Jadad: study quality (Jadad score ≥ 3 vs Jadad score ≤ 3)

Sanfilippo, 2017 [21]

Newcastle-Ottawa Scale tool: Low risk of bias score ranging between 6 and 9

Nagappa, 2017 [22]

Newcastle-Ottawa scale: good quality is score ≥ 8 of 9

Schnabel, 2011 [23]

Oxford scale: low quality study with 2 points

Schnabel, 2010 [24]

Oxford scale: the studies were rated as high (Oxford scale ≥3) or low (Oxford scale >3) quality studies.

Suppan, 2016 [25]

Oxford: lower quality studies (Oxford score < 4)

Schnabel, 2012 [26]

Oxford: ‘high quality’: Oxford scale > 3 versus ‘low quality’: Oxford scale 3 points

Schnabel, 2013 [27]

Oxford: high-quality trials [modified Oxford scale > 4] vs low-quality trials [modified Oxford scale ≤4

Schnabel, 2013 [28]

Oxford: high-quality trials [modified Oxford scale > 4] vs low-quality trials [modified Oxford scale ≤4

Mishriky, 2012 [29]

Oxford: restricting the analysis to studies with a modified Oxford score of 4 or higher