Table 3 Quality assessment of comparative non-randomized studies
Studies | Country | Pre-intervention and at-intervention domains | Post-intervention domains | Overall risk of bias | |||||
|---|---|---|---|---|---|---|---|---|---|
Bias due to confounding | Bias in selection of participants in 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 | |||
Harder 2013 [16] | Germany | M | L | L | L | L | M | L | M |
Isaac 2015 [8] | Canada | M | M | L | L | L | M | L | M |
Hwang 2015 [9] | USA | M | L | L | L | L | M | L | M |
Gunay 2016 [11] | Turkey | M | M | M | L | L | M | L | M |
Mueller2016 [7] | Germany | M | M | M | L | L | M | L | M |
Walz 2016 [26] | Germany | M | L | L | L | M | L | L | M |