PBM Module 4a Risk-of-bias-tabel
Risk of bias table for intervention studies (randomized controlled trials; based on Cochrane risk of bias tool and suggestions by the CLARITY Group at McMaster University)
Study reference (first author, publication year) |
Was the allocation sequence adequately generated? Definitely yes |
Was the allocation adequately concealed? Definitely yes |
Blinding: Was knowledge of the allocated interventions adequately prevented? Were patients blinded? Definitely yes |
Was loss to follow-up (missing outcome data) infrequent? Definitely yes |
Are reports of the study free of selective outcome reporting? Definitely yes |
Was the study apparently free of other problems that could put it at a risk of bias? Definitely yes |
Overall risk of bias If applicable/necessary, per outcome measure LOW |
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Loeb, 2022 |
Definitely yes Reason: Trial participants were randomly assigned (1:1) to either medical masks or N95 respirators. Participants were randomly assigned centrally by a study statistician who generated the sequence using a computerized random number generator. Randomization was stratified by site in permuted blocks of 4. The randomization scheme was provided by an interactive web response system and performed centrally. |
Definitely yes Reason: Investigators were blinded to the group assignment |
Definitely no Reason: it was not possible to conceal the identity of the medical mask or N95 respirator assignment to the study staff or participants |
Definitely yes Reason: loss to-follow-up was minimal and an ITT-analysis was performed |
Definitely yes Reason: All relevant outcomes were reported, and the trial was registered (ClinicalTrials.gov: NCT04296643) |
Definitely no Reason: Potential acquisition of SARS-CoV-2 through household and community exposure, heterogeneity between countries, uncertainty in the estimates of effect, differences in self-reported adherence, differences in baseline antibodies, and between-country differences in circulating variants and vaccination. |
HIGH |