Table 3.

Risk of bias assessment for individual studies (nonrandomized trials).

Study	Bias due to confounding	Bias in participant selection	Bias in classification of interventions	Bias due to departures from intended interventions	Bias due to missing data	Bias in measurement of outcomes	Bias in selection of the reported result	Overall bias
Lawitz et al. [29]	NA	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	NA
Kowdley et al. [27]	NA	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	NA
Gane et al. [24]	NA	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	NA
Curry et al. [21]	NA	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	NA
Abergel et al. [20]	NA	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	NA
Jacobson et al. [26]	NA	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	NA
Gane et al. [25]	Serious risk	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Serious risk
Nguyen et al. [30]	Serious risk	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Serious risk
Wei et al. [32]	Serious risk	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Serious risk
Thuy et al. [31]	Serious risk	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Serious risk

^∗NA: nonapplicable.