Validation of the Korean version of inflammatory Rasch-built Overall Disability Scale in patients with inflammatory neuropathy.

Background And Aims: The Inflammatory Rasch-built Overall Disability Scale (I-RODS) is an effective activity measure for use in inflammatory peripheral neuropathy. The aim of this study was to validate the Korean version of the I-RODS in patients with chronic inflammatory demyelinating polyneuropathy (CIDP), Guillain-Barré syndrome (GBS), anti-myelin-associated glycoprotein (MAG) neuropathy, and autoimmune nodopathy.

Methods: A total of 120 patients underwent clinical evaluations, which included the I-RODS, Inflammatory Neuropathy Cause and Treatment (INCAT) assessment, and Jamar grip strength (kg) measurement. Follow-up assessments were performed for 83 patients during their regular clinic visits. To estimate the test-retest reliability of the I-RODS, the scale was reapplied to a subset of 16 patients within 2-7 days of the initial test. Overall, reliability, validity, and responsiveness of the I-RODS were evaluated.

Results: Internal consistency was good, as indicated by a person separation index of 0.966. The raw and standardized Cronbach's alpha values were both 0.974. The test-retest reliability analyzed using the intraclass correlation coefficient (ICC) was also high (ICC = 0.972). The I-RODS showed a strong correlation with INCAT scores (ρ = -0.81, p < .001) and a moderate correlation with grip strength (ρ = 0.61, p < .001). Furthermore, the sensitivity for detecting clinically meaningful improvement was highest for grip strength (60.4%) followed by I-RODS (52.1%), while for capturing deterioration, it was highest for I-RODS (80.0%).

Interpretation: The Korean version of the I-RODS is a reliable and valid tool for measuring disability in patients with inflammatory neuropathy. The I-RODS is useful for both clinical practice and research applications.