Poor reliability between Cochrane reviewers and blinded external reviewers when applying the Cochrane risk of bias tool in physical therapy trials.
OBJECTIVE
To test the inter-rater reliability of the RoB tool applied to Physical Therapy (PT) trials by comparing ratings from Cochrane review authors with those of blinded external reviewers.


METHODS
Randomized controlled trials (RCTs) in PT were identified by searching the Cochrane Database of Systematic Reviews for meta-analysis of PT interventions. RoB assessments were conducted independently by 2 reviewers blinded to the RoB ratings reported in the Cochrane reviews. Data on RoB assessments from Cochrane reviews and other characteristics of reviews and trials were extracted. Consensus assessments between the two reviewers were then compared with the RoB ratings from the Cochrane reviews. Agreement between Cochrane and blinded external reviewers was assessed using weighted kappa (κ).


RESULTS
In total, 109 trials included in 17 Cochrane reviews were assessed. Inter-rater reliability on the overall RoB assessment between Cochrane review authors and blinded external reviewers was poor (κ  =  0.02, 95%CI: -0.06, 0.06]). Inter-rater reliability on individual domains of the RoB tool was poor (median κ  = 0.19), ranging from κ  =  -0.04 ("Other bias") to κ  =  0.62 ("Sequence generation"). There was also no agreement (κ  =  -0.29, 95%CI: -0.81, 0.35]) in the overall RoB assessment at the meta-analysis level.


CONCLUSIONS
Risk of bias assessments of RCTs using the RoB tool are not consistent across different research groups. Poor agreement was not only demonstrated at the trial level but also at the meta-analysis level. Results have implications for decision making since different recommendations can be reached depending on the group analyzing the evidence. Improved guidelines to consistently apply the RoB tool and revisions to the tool for different health areas are needed.
CLEAR (Connecting Leadership and Research) Outcomes Research Program, Faculty of Nursing, University of Alberta, Edmonton, Alberta, Canada; Faculty of Rehabilitation Medicine, Department of Physical Therapy, University of Alberta, Edmonton, Alberta, Canada.
Susan
S
Armijo-Olivo
Emergency Medicine Strategic Clinical Network, Alberta Health Services, Department of Emergency Medicine, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canadá
Maria
M
Ospina
Department of Physical Therapy, Florida International University, Miami, Florida, United States of America.
Bruno R
BR
da Costa
Institute of Social & Preventive Medicine, University of Bern, Bern, Switzerland.
Matthias
M
Egger
Orthodontic Graduate Program, School of Dentistry, University of Alberta, Edmonton, Alberta, Canadá
Humam
H
Saltaji
Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada; Catholic University of Maule, Department of Physical Therapy, Talca, Maule, Chile.
Jorge
J
Fuentes
Rehabilitation Research Center, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada.
Christine
C
Ha
CLEAR (Connecting Leadership and Research) Outcomes Research Program, Faculty of Nursing, University of Alberta, Edmonton, Alberta, Canada.
Greta G
GG
Cummings
D015982:Bias; D006801:Humans; D026741:Physical Therapy Modalities; D016032:Randomized Controlled Trials as Topic; D015203:Reproducibility of Results; D012107:Research Design; D012196:Review Literature as Topic