Review Article
The PEDro scale provides a more comprehensive measure of methodological quality than the Jadad Scale in stroke rehabilitation literature

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Abstract

Objective

To systematically compare the PEDro scale and the Jadad scale when applied to the stroke rehabilitation literature.

Study Design and Setting

A literature search of multiple databases was used to identify all trials from 1968 through 2002. Each article was reviewed and assigned quality scores according to PEDro and Jadad criteria. Quality scores for both scales were compared using descriptive statistics. The correlation between the scales was estimated using the Pearson product moment correlation coefficient.

Results

272 randomized controlled trials were retrieved and subjected to quality scoring to both the PEDro scale and the Jadad scale. Mean scores (with standard deviation) for the PEDro and Jadad scales were 5.78 (1.4) and 2.46 (1.1), respectively. The Pearson coefficient determined the PEDro and Jadad scales to be significantly correlated (r = .59, P < .01). Although significant, the correlation was not deemed to be very strong. When applied to physical or rehabilitation therapy studies only, the scales were slightly less correlated (r = .49, P < .01) than among drug-based studies (r = .52, P < .01).

Conclusion

In the stroke rehabilitation literature, where double-blinding studies are often not possible due to the nature of the interventions, breaking down the levels of blinding and accounting for concealed allocation, intention-to-treat, and attrition is important. Accordingly, the PEDro scale provides a more comprehensive measure of methodological quality of the stroke literature.

Introduction

Some heterogeneity in the results of efficacy studies is inevitable, even when all studies employ bias-minimizing designs such as the randomized controlled trial. Scales have been devised to rate the methodological quality of different studies, to aid the interpretation of conflicting results. A recent study reported that at least 25 different rating scales have been published [1]. The present study replicated the work of earlier authors who found that the conclusions of meta-analyses are themselves dependent on the rating scale used. So, although each scale was originally created in part to help detect the true signal amidst the noise of multiple individual studies, the multiplicity of scales has in fact added another source of heterogeneity to the published literature.

As part of the abstraction process for the Evidence-Based Review of Stroke Rehabilitation (EBRSR) [2], the methodological rigor of included articles was assessed. Two quality assessment tools were considered for rating the quality of the primary articles: the Jadad quality criteria [3], chosen for its brevity and widespread use, and the Physiotherapy Evidence-Based Database (PEDro) scale, newly developed by the Centre for Evidence-Based Physiotherapy (CEBP) [4], ultimately chosen for its physiotherapy angle. During the decision process, how the two scales compare to one another was questioned. After completion of the first edition of the edition of the EBRSR [2], the primary studies were reassessed using the Jadad scale to compare how the scores of the Jadad scale compared to the scales yielded from the PEDro scale.

Our objective was to systematically examine the correlation of the PEDro scale and the Jadad quality criteria. Given that the PEDro and Jadad scales were originally designed to address methodological issues of specific types of research (physiotherapy and pain studies, respectively) and that the stroke rehabilitation literature contains both pharmaceutical and physical therapy–based studies, it was of interest to determine if and how the two quality scales were correlated.

Section snippets

Methods

The EBRSR was created to systematically review current practices in stroke rehabilitation. As part of the process of an evidence-based review of the stroke rehabilitation literature, 272 randomized controlled trials (RCTs) were rated on their methodological rigor [2].

A detailed account of the methods is reported elsewhere [2]. A brief description of the methods is provided below.

Main analysis

We retrieved 272 articles addressing some aspect of stroke rehabilitation and subjected these to quality scoring according to both the PEDro scale and the Jadad scale. Average score (with SD) for the PEDro and Jadad scale were 5.78 (1.41) and 2.46 (1.1), respectively (Table 1). Breakdowns of both scales are presented in Table 2, Table 3.

The Pearson coefficient determined the PEDro and Jadad scales to be significantly positively correlated (r = .594, P < .01). When we generated a scatter plot,

Discussion

Both the PEDro and the Jadad scales are validated quality assessment tools, but they correlate with one another weakly. One possible reason for this weak association could be that the scales were originally developed to capture the design and conduct of particular types of study (physiotherapy vs. pain studies). As such, each scale approaches the assessment of a study in slightly different ways.

Similar scale items on the two scales did not correlate to 1 or close to 1, thereby, which suggests

Acknowledgments

Funded by a grant from the Ministry of Health and Long-Term Care of Ontario, the Heart and Stroke Foundation of Ontario, Parkwood Hospital and the Canadian Stroke Network. The following individuals were involved in assessment of the individual articles: Haider Mannan, Sarah Sanders, Jonathon Herbert, Shelly Cross-Mellor, Mike Boisevert, Keith Swyer.

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1

Present address: Department of Epidemiology and Biostatistics, McGill University, Montreal, Québec, Canada.

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