Neurology 2014 Dec 5;83(23):2124-32. Epub 2014 Nov 5.
From the Department of Neurology (T.H.P.D., E.K.V., C.G.F., I.S.J.M.), University Medical Centre Maastricht; Department of Neurology (S.I.v.N., P.A.v.D.), Erasmus Medical Centre Rotterdam, the Netherlands; Department of Neurology (K.C.G.), St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA; Department of Neurology (W.L.V.d.P., N.C.N., L.H.v.d.B.), Rudolf Magnus Institute of Neuroscience University Medical Centre Utrecht, the Netherlands; Department of Neurological Sciences (E.N.-O.), Milan University, Humanitas Clinical Institute, Rozzano, Milan, Italy; Department of Neurology (J.M.L.), Hôpital de la Salpêtrière, Paris, France; Department of Neurology (P.Y.K.V.d.B.), Catholique University of Louvain, Belgium; Department of Clinical Neurosciences (G.L.), 3rd Neurology Unit, Milan, Italy; Department of Neurology (V.B., H.K.), Toronto General Hospital, Canada; Department of Neurology (M.P.T.L.), Centre for Neuromuscular Disease, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK; Department of Neurology (J.P.), Centre de Référence des Maladies Neuromusculaires et de la SLA, Hôpital de La Timone, Marseille, France; Department of Neurology (A.J.v.d.K.), Academic Medical Centre, Amsterdam, the Netherlands; Department of Neurology (A.F.H.), London Health Science Center, London, Canada; Department of Neurology (D.R.C.), Johns Hopkins School of Medicine, Baltimore, MD; and Department of Neurology (I.S.J.M.), Spaarne Hospital, Hoofddorp, the Netherlands.
Objectives: We performed responsiveness comparison between the patient-reported Inflammatory Rasch-built Overall Disability Scale (I-RODS) and the widely used clinician-reported Inflammatory Neuropathy Cause and Treatment-Overall Neuropathy Limitation Scale (INCAT-ONLS) in patients with Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), and immunoglobulin M-monoclonal gammopathy of undetermined significance related polyneuropathy (IgM-MGUSP).
Methods: One hundred thirty-seven patients (GBS: 55, CIDP: 59, IgM-MGUSP: 23) with a new diagnosis or clinical relapse assessed both scales. Patients with GBS/CIDP were examined at 0, 1, 3, 6, and 12 months; patients with IgM-MGUSP at 0, 3, and 12. We subjected all data to Rasch analyses, and calculated for each patient the magnitude of change on both scales using the minimal clinically important difference (MCID) related to the individual standard errors (SEs). A responder was defined as having an MCID-SE ≥1.96. Individual scores on both measures were correlated with the EuroQoL thermometer (heuristic responsiveness).
Results: The I-RODS showed a significantly higher proportion of meaningful improvement compared with the INCAT-ONLS findings in GBS/CIDP. For IgM-MGUSP, the lack of responsiveness during the 1-year study did not allow a clear separation. Heuristic responsiveness was consistently higher with the I-RODS.
Conclusion: The I-RODS more often captures clinically meaningful changes over time, with a greater magnitude of change, compared with the INCAT-ONLS disability scale in patients with GBS and CIDP. The I-RODS offers promise for being a more sensitive measure and its use is therefore suggested in future trials involving patients with GBS and CIDP.