Table 2.

Bias Assessment Results

Study	Bias Due to Confounding	Bias in the Selection of Participants in the Study	Bias in the Classification of Interventions	Bias Due to Deviations from Intended Interventions	Bias Due to Missing Data	Bias in the Measurement of Outcome	Bias in the Selection of the Reported Results	Overall Study Bias Rating
Assimon et al7	Serious	Low	Low	Low	Low	Low	Low	Serious
Shireman et al6	Serious	Moderate	Low	Low	Low	Low	Moderate	Serious
Weir et al10	Moderate	Serious	Low	Moderate	Low	Moderate	Moderate	Serious
Wu et al8	Moderate	Low	Low	Low	Serious	Low	Moderate	Serious

Note: Domain-specific and overall bias ratings of the 4 included studies.