Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Ultrasound Evaluation Reveals the Reason for High Interrater Variability in Joints of the 66/68 Joint Count.

Witt2,  Matthias Nikolaus, Ronneberger1,  Monika, Schnez3,  Amelie, Laubender4,  Ruediger, Engelbrecht1,  Matthias, Kavanaugh6,  Arthur, Schulze-Koops5,  Hendrik

Department of Internal Medicine 3, University of Erlangen-Nuremberg, Erlangen, Germany
Division of Rheumatology, Ludwig-Maximilians-University, Munich, Germany
Division of Rheumatology, Ludwig-Maximilians-University, Munich, Germany
Institute of Medical Informatics, Biometry and Epidemiology (IBE), Ludwig-Maximilians-University, Munich, Germany
Ludwig-Maximilians-University, Munich, Germany
University of California-San Diego, La Jolla, CA

Background:

In patients with rheumatoid arthritis, joint counts are the key outcome parameter in clinical trials as well as in daily clinical practice. It has been shown, however, that there is a huge variability between different assessors of the same patient. In a previous paper we have shown, that this can be reduced by a standardised training of the EULAR examination technique. We have also shown, however, that the effect of standardisation is worse for the 66/68 than for the 28 joint count.

Objectives:

To evaluate the reason for the higher interrater disagreement in the assessment of the 68/66 in contrast to the 28 joint count. Is it the greater difficulty in assessing the joints of the lower extremity and can this be ruled out by ultrasonography?

Methods:

Participants of joint examination seminars evaluated a given RA patient before and after they were made familiar with the EULAR examination technique. Joints were rated positive or negative for tenderness and swelling without graduation. The amount of tender and swollen joints as well as the variability between the examiners (groups of 4–6 trainees per patient) before and after the training were compared. For every single joint, the degree of agreement was calculated using the Fleiss-Kappa test. In a subgroup of 40 patients, the clinical results were compared to an independent ultrasound examination of the MTP joints.

Results:

340 health professionals participating in standardised joint assessment trainings were evaluated. 256 were instructed in the 68/66, 84 in the 28 joint count. For both joint counts, the disagreement between different examiners was higher for the dimension of joint swelling than for tenderness. After the training of the EULAR examination technique, there was a significant reduction of interrater variability, which was more pronounced in the 28 than in the 68/66 joint count. Comparisons between manual and ultrasound assessment revealed, that concerning the dimension of swelling manual examination has a very low sensitivity and high variability in the joints of the feet.

Conclusion:

Standardisation of the joint examination technique significantly reduces variability. The relatively better performance of the 28 joint count is partly due to the higher number of examined joints in the 68/66 joint count. Another reason is, that the joints of the feet, although they are more often rated negative by manual than by ultrasound evaluation, tend to imply a higher disagreement between different assessors.

To cite this abstract, please use the following information:
Witt, Matthias Nikolaus, Ronneberger, Monika, Schnez, Amelie, Laubender, Ruediger, Engelbrecht, Matthias, Kavanaugh, Arthur, et al; Ultrasound Evaluation Reveals the Reason for High Interrater Variability in Joints of the 66/68 Joint Count. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1781
DOI: 10.1002/art.29546

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