The Longitudinal Reliability and Responsiveness of the OMERACT Hand Osteoarthritis Magnetic Resonance Imaging Scoring System (HOAMRIS).

Objective: To evaluate the interreader reliability of change scores and the responsiveness of the OMERACT Hand Osteoarthritis (OA) Magnetic Resonance Image (MRI) Scoring System (HOAMRIS).

Methods: Paired MRI (baseline and 5-yr followup) from 20 patients with hand OA were scored with known time sequence by 3 readers according to the HOAMRIS: Synovitis, erosive damage, cysts, osteophytes, cartilage space loss, malalignment, and bone marrow lesions (BML; 0-3 scales with 0.5 increments for synovitis, erosive damage, and BML). Interreader reliability for status and change scores were assessed by intraclass correlation coefficients (ICC), percentage exact agreement and percentage close agreement (PEA/PCA), and smallest detectable change (SDC). Responsiveness was assessed by standardized response means (SRM).

Results: Cross-sectional interreader ICC were good to very good (≥ 0.74) for all features except synovitis, cysts, and malalignment (ICC 0.50-0.58). The range of change values was small, leading to low ICC for change scores. The SDC values for sum scores (total range 0-24) varied between 1.97-3.05 (except 1.08 for malalignment). For status scores, PEA/PCA on scores in individual joints across the readers were 8.1-50.0 and 43.8-78.1, respectively. Similarly, PEA/PCA for change scores were 20.6-63.8 and 66.3-93.1, respectively. All features except cysts and BML demonstrated good responsiveness with higher SRM for sum scores (range 0.46-1.62) than for scores in individual joints (range 0.24-0.73).

Conclusion: Good to very good interreader ICC values were found for cross-sectional readings, whereas the longitudinal reliability was lower because of a smaller range of change scores. All features, except cysts and BML, showed good responsiveness.