PEDro or Cochrane to assess the quality of physiotherapy trials? A meta-epidemiological study

Article type
Authors
Armijo-Olivo S1, da Costa BR2, Cummings GG1, Ha C1, Fuentes J1, Saltaji H1, Egger M3
1University of Alberta, Canada
2Institute of Primary Health Care, University of Bern, Switzeralnd
3Institute of Social & Preventive Medicine (ISPM), University of Bern, Switzerland
Abstract
Background: The use of different tools for evaluating the quality of randomized controlled trials (RCTs) in systematic reviews (SRs) can lead to discrepancies and skewed interpretations of SR results. The PeDro tool, which uses summary scores to determine the quality of RCTs is commonly used in physical therapy (PT). An alternative approach is based on an assessment of individual components such as the items used in the Cochrane 'Risk of bias' (RoB) tool.
Objective: To determine the agreement between the Cochrane and the PeDro approaches to identifying physiotherapy trials of adequate quality.
Methods: We conducted a meta-epidemiological study. RCTs in PT were identified by searching the Cochrane Database of Systematic Reviews for meta-analysis of PT interventions. Final scores for PeDro and Cochrane assessments were extracted. We defined trials of adequate quality as having adequate sequence generation, concealment of allocation, and blinding of outcome assessors (based on the Cochrane RoB tool) or as trials with a PEDro score of at least 5 or 6 points, the cut-offs widely used in the literature. We calculated the kappa statistics to assess the agreement between PeDro scores and the Cochrane approach for classifying trial quality. We compared effect sizes from trials of adequate quality for each meta-analysis between the two approaches.
Results: Forty-one Cochrane reviews and 353 trials of PT interventions were included. All meta-analyses included trials of adequate quality based on a ≥ 5 PEDro points cut-off and 37 (87.8%) included trials of adequate quality based on a ≥ 6 cut-off. Nineteen meta-analyses did not include trials of adequate quality according to the Cochrane approach. Agreement between PeDro and Cochrane was poor for PeDro scores of ≥ 5 points (k = 0.12; 95% CI 0.07 to 0.16), slight agreement for ≥ 6 points (k = 0.24; 95% CI 0.16 to 0.32), and ≥ 7 points (k = 0.39; 95% CI 0.286 to 0.510), and fair agreement (k = 0.44; 95% CI 0.314 to 0.574) ≥ 8 points (Figure 1).
Conclusions: The PeDro and Cochrane approaches lead to different sets of trials of adequate quality. A consistent approach to assessing RoB in trials of PT should be adopted.