Author and year	Bias due to confounding	Bias in selection of participants into the study	Bias in classification of interventions	Bias due to deviations from intended interventions	Bias due to missing data	Bias in measurement of outcomes	Bias in selection of the reported result	Overall risk of bias
Hsieh 2005	Moderate	Low	Low	Low	Moderate	Moderate	Low	Moderate
Pang 2003	Moderate	Low	Low	Low	Moderate	Moderate	Low	Moderate
Park 2020	Serious	Low	Low	Low	Moderate	Moderate	Low	Serious
Wang 2007	Moderate	Low	Low	Low	Moderate	Moderate	Low	Moderate