Table 5.

Quality indicators across reviewed studies

	Method for selecting sample	Methods to control cofounding		Statistical methods		Methods for measuring outcomes
		Sample size	Identification of cofounders	Appropiate analyses	Missing data	Outcome measures	Objective assessment
CM-I adult population
Pearce et al. (2006)	↑	↑	↑	↑	↓	↔	↓
Kumar et al. (2011)	↔	↑	↑	↔	↓	↔	↓
Del Casale et al. (2012)	↑	↑	↑	↑	↓	↔	↓
Mahgoub et al. (2012)	↑	↑	↑	↑	↓	↔	↓
Allen et al. (2014)	↔	↔	↔	↓	↓	↓	↓
Klein et al. (2014)	↑	↑	↔	↑	↓	↔	↓
Allen et al. (2018)	↔	↓	↑	↔	↓	↔	↓
Houston et al. (2018)	↔	↔	↓	↓	↓	↓	↓
García et al. (2018b)	↔	↔	↓	↓	↓	↓	↓
Besteiro and Torres (2018)	↔	↔	↑	↓	↓	↓	↓
Lázaro et al. (2018)	↓	↓	↔	↓	↓	↓	↓
García et al. (2018a)	↓	↓	↓	↓	↓	↓	↓
Lacy et al. (2019)	↔	↔	↔	↔	↓	↓	↓
Houston et al. (2019)	↔	↔	↓	↓	↓	↓	↓
García et al. (2020b)	↔	↔	↓	↓	↓	↓	↓
García et al. (2020a)	↔	↔	↓	↓	↓	↓	↓
Almotairi et al. (2020)	↔	↑	↔	↓	↓	↓	↓
Houston et al. (2020)	↔	↔	↓	↓	↓	↓	↓
Houston et al. (2021)	↔	↔	↓	↓	↓	↓	↓
Seaman et al. (2021)	↔	↔	↓	↓	↓	↓	↓
Yilmaz et al. (2022)	↔	↔	↑	↔	↓	↓	↓
CM-I pediatric population
Gabrielli et al. (1998)	↑	↑	↑	↑	↓	↔	↓
Grosso et al. (2001)	↑	↑	↑	↑	↓	↔	↓
Haapanen (2007)	↑	↑	↑	↑	↓	↑	↔
Novegno et al. (2008)	↑	↑	↑	↑	↓	↔	↓
Riva et al. (2011)	↑	↑	↑	↑	↓	↔	↓
Lacy et al. (2016)	↔	↓	↑	↔	↓	↓	↔
Sari and Ozum (2021)	↔	↑	↑	↔	↓	↓	↓

Quality indicators have been selected following the adapted version of modified Newcastle–Ottawa scale (Bawor et al., 2014)

High risk of bias: ↑; Moderate risk of bias: ↔ ; Low risk of bias: ↓