Table 2.

Risk of non-randomized controlled trial bias in this systematic review

Study	Confounding	Selection of participants	Classificationof intervention	Deviations from intended interventions	Missing data	Measurement of outcomes	Selection of the reported result	Overall
Bissonnette et al. [7]	Moderate	Moderate	Low	Low	Low	Low	Low	Moderate
Mirchi et al. [8]	Moderate	Moderate	Low	Low	Low	Low	Low	Moderate
Siemionow et al. [14]	Low	Low	Low	Low	Low	Low	Low	Low
Siemionow et al. [17]	Moderate	Moderate	Low	Low	Low	Low	Low	Moderate
Hanna et al. [10]	Moderate	Moderate	Serious	Low	Low	Low	Moderate	Serious
Scherer et al. [11]	Low	Low	Low	Low	Low	Low	Low	Low
Wei et al. [12]	Low	Low	Low	Low	Low	Low	Low	Low
Jecklin et al. [9]	Moderate	Moderate	Low	Low	Low	Low	Low	Moderate
Huang et al. [13]	Moderate	Low	Low	Low	Low	Low	Low	Moderate