Validation of the OMERACT Magnetic Resonance Imaging Joint Space Narrowing Score for the Wrist in a Multireader Longitudinal Trial.

Abstract

To assess the intrareader and interreader agreement and sensitivity to change of the Outcome Measures in Rheumatology (OMERACT) Rheumatoid Arthritis Magnetic Resonance Imaging Joint Space Narrowing (RAMRIS-JSN) score in the rheumatoid arthritis (RA) wrist in a longitudinal multireader exercise. Coronal T1-weighted MR image sets of 1 wrist from 20 patients with early RA were assessed twice for JSN at 17 sites at baseline and after 36 or 60 months by 4 readers blinded to patient data but not time order. The joints were scored 0-4 according to the OMERACT RAMRIS-JSN score. Intraclass correlation coefficients (ICC), smallest detectable change (SDC), percentage exact/close agreement (PEA/PCA), and standardized response mean (SRM) were calculated. Median baseline and change score was 10.3 and 1.9, respectively. Intrareader ICC for baseline and change scores was good (≥ 0.50) to very good (≥ 0.80) for all and 3 of 4 readers, respectively. Interreader ICC was very good for change (0.93), while poor for baseline score if all 4 readers were included (0.36), but very good if 1 reader was excluded (0.87). Intrareader and interreader SDC was low (2.34-3.18), except for the intrareader SDC for 1 reader (6.75). The mean PEA/PCA was high for baseline and change scores both within and between the readers (51.5-99.2), except for interreader baseline PEA (14.4). SRM was moderate for all readers (0.55-0.77). The OMERACT RAMRIS-JSN score showed high overall intrareader and interreader reliability, and moderate sensitivity to change, supporting inclusion of the measure as part of the OMERACT RAMRIS system.