Is the Doppler Ultrasound Score More Reliable than the Grey Scale Ultrasound Score in Assessing the Rheumatoid Arthritis Patient’s Joints?

Background: Rheumatoid arthritis (RA) is a complex disease with multiple faces, one of them being its activity. At the moment, there are multiple-choice tools to assess the activity of the disease, no one gaining the complete status of “gold standard”. In the evaluation of the disease activity biological and non-biological methods are used and interposed. The methods are more or less subjective, thus the validation of measurements in RA is highly relevant.
Objective: The main objective of the study was to evaluate the reliability of the Doppler Ultrasound score versus the Grey scale ultrasound score in the assessment of the disease activity in rheumatoid arthritis patients.
Methods: A number of 66 patients diagnosed with rheumatoid arthritis were assessed with the B-mode and consequently Colour Doppler ultrasound score system. The joints examined were the second and the third metacarpal (MCP) and proximal interphalangeal joints (PIP) on the dorsal and ventral side. Two thousand twelve images were stored and evaluated on both scales. Data were analysed with GraphPad Prism 5.0. In order to assess the validity of the ultrasound methods used in the study as non-biological markers for the activity of rheumatoid arthritis Pearson correlation, Bland-Altman method and linear regression were used.
Results: A positive correlation was found when analyzed the two methods of assessment of the disease activity in rheumatoid arthritis. A single mismatch was found (Pearson correlation and linear regression) at the level of the second metacarpal on the ventral and right side when compared the Doppler ultrasound versus the Grey scale score, but we presumed that this is due to the particularity of the individual outcome. The Bland-Altman method showed that the Grey scale of quantification overrated the scores versus the Color Doppler Ultrasound scale.
Conclusions: The semi-quantitative Color Doppler method which assesses the intra-joint activity in rheumatoid arthritis patients was validated in our research to be further used. Even though none of the statistic methods used for validating the Doppler score in our study showed significant statistic differences between them, it is for the best to apply all of them for validating any intended method to be used in any study.