The psychometric properties of the Italian version of the PEDro Scale

INTRODUCTION: The present study aimed to validate the Italian version of the Physiotherapy Evidence Database (PEDro) scale to assess the methodological quality of Randomized Controlled Trials and to evaluate the scale’s psychometric properties. EVIDENCE ACQUISITION: The papers in the PEDro database were evaluated with the PEDro Scale and the Cochrane Risk of Bias Tool and the Jadad Scale. For the assessment of intra-rater reliability and inter-rater reliability the Intraclass Correlation Coefficient (ICC) was calculated. The internal consistency of the PEDro Scale was evaluated using Cronbach’s α. Pearson’s Correlation Coefficient was used to compare the PEDro Scale scores with those obtained with the Cochrane Risk of Bias Tool and the Jadad Scale. The cut-off of the PEDro Scale used to define a high- or low-quality study was evaluated with the receiver operating characteristic curve. EVIDENCE SYNTHESIS: The total Cronbach α value was 0.537. As shown by the ICCs, intra-rater reliability ranged from 0.94 to 0.98, with a high level of agreement between the two ratings. Inter-rater test-retest evaluation revealed a statistically significant correlation between the PEDro score obtained from the evaluation found within the PEDro database and two different operators. An ICC score = 0.969 (range 0.951-0.981) was obtained. CONCLUSIONS: The PEDro Scale has proven to be an instrument with good test-retest reliability, excellent construct validity, and good accuracy. However, the scale has little internal validity, probably linked to the presence of an important ceiling/floor effect in half of the items that comprise it. The 5.5 threshold value was also identified as the cut-off value for the scale.