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The provisional OMERACT ultrasonography score for giant cell arteritis
Christian Dejaco1,2, Cristina Ponte3,4, Sara Monti5,6
1Department of Rheumatology, Medical University of Graz, Graz, Steiermark, Austria christian.dejaco@gmx.net.
Insights
A new ultrasonography score, the OMERACT GCA Ultrasonography Score (OGUS), was developed to monitor giant cell arteritis (GCA) disease activity. This reliable and sensitive tool shows promise for clinical trials in GCA patients.
Area of Science:
- Rheumatology
- Medical Imaging
- Clinical Trials
Background:
- Giant cell arteritis (GCA) is a systemic vasculitis affecting large arteries.
- Accurate monitoring of disease activity is crucial for effective GCA management.
- Current monitoring methods may require improvement in sensitivity and specificity.
Purpose of the Study:
- To develop and validate an Outcome Measures in Rheumatology (OMERACT) ultrasonography score for assessing disease activity in GCA.
- To evaluate the metric properties, including reliability and sensitivity to change, of the proposed score.
Main Methods:
- The OMERACT Instrument Selection Algorithm guided the development process.
- Seven Delphi rounds involving 49 experts were conducted.
- An online reliability exercise and a prospective cohort study were performed to assess metric properties.
Main Results:
- The OMERACT GCA Ultrasonography Score (OGUS) achieved 92.7% agreement among participants.
- High interrater (ICC 0.72-0.84) and intrareader (ICC 0.91) reliability were demonstrated.
- The OGUS showed large to very large sensitivity to change and moderate correlations with established GCA activity markers.
Conclusions:
- A provisional OGUS has been developed, demonstrating good reliability and sensitivity to change.
- The OGUS is a promising tool for monitoring disease activity in GCA within clinical trial settings.
Objectives:
To develop an Outcome Measures in Rheumatology (OMERACT) ultrasonography score for monitoring disease activity in giant cell arteritis (GCA) and evaluate its metric properties.
Methods:
The OMERACT Instrument Selection Algorithm was followed. Forty-nine members of the OMERACT ultrasonography large vessel vasculitis working group were invited to seven Delphi rounds. An online reliability exercise was conducted using images of bilateral common temporal arteries, parietal and frontal branches as well as axillary arteries from 16 patients with GCA and 7 controls. Sensitivity to change and convergent construct validity were tested using data from a prospective cohort of patients with new GCA in which ultrasound-based intima-media thickness (IMT) measurements were conducted at weeks 1, 3, 6, 12 and 24.
Results:
Agreement was obtained (92.7%) for the OMERACT GCA Ultrasonography Score (OGUS), calculated as follows: sum of IMT measured in every segment divided by the rounded cut-off values of IMTs in each segment. The resulting value is then divided by the number of segments available. Thirty-five members conducted the reliability exercise, the interrater intraclass correlation coefficient (ICC) for the OGUS was 0.72-0.84 and the median intrareader ICC was 0.91. The prospective cohort consisted of 52 patients. Sensitivity to change between baseline and each follow-up visit up to week 24 yielded standardised mean differences from -1.19 to -2.16, corresponding to large and very large magnitudes of change, respectively. OGUS correlated moderately with erythrocyte sedimentation rate, C reactive protein and Birmingham Vasculitis Activity Score (corrcoeff 0.37-0.48).
Conclusion:
We developed a provisional OGUS for potential use in clinical trials.
