Table 3 Overall risk of bias assessments for individual non-randomized studies according to standardized criteria (ROBINS-I [6]), using the tools’ ascending scale of risk (low, moderate, serious, critical, or No Information (NI), meaning the risk of bias could not be assessed)
Non-randomized studies (ROBINS-I assessment criteria) | Sivertsen and Løe, 2019 [10] | Røhne et al., 2016 [11] |
|---|---|---|
Bias due to confounding | Critical | Serious |
Bias in selection of participants | NI | NI |
Bias in classification of interventions | Moderate | Serious |
Bias in deviations from intervention | Low | Low |
Bias due to missing data | NI | Critical |
Bias in measurement of outcomes | Serious | Serious |
Bias in selective reporting | Moderate | Moderate |
Overall Bias | Critical | Critical |
Comments/direction of bias | Unpredictable | Unpredictable |