Background No consensus exists which quality of life (QoL) measure should be used in patients with inflammatory neuropathies. Moreover, most QoL measures are ordinal-based scales with their known deficiencies.
Objectives To establish a new disease-specific interval-based QoL questionnaire in inflammatory neuropathies (IN-QoL) using the Rasch model and evaluate its scientific properties (validity, reliability and responsiveness).
Methods 264 patients with inflammatory neuropathies completed six commonly used QoL questionnaires. The obtained data were stacked and subjected to Rasch analysis. Responsiveness was determined by using the concept of minimum clinically important differences related to varying individually obtained SEs (responsiveness definition: MCID-SE≥1.96 after 1-year follow-up compared with baseline).
Results The IN-QoL fulfilled all Rasch’s model requirements with high internal reliability values (patient separation index of 0.94), except being multidimensional. Additional factor analysis resulted in two (functional and mental) subsets that were unidimensional on their own. The IN-QoL showed good correlation with the EuroQol-health quality visual analogue scale (EQ-VAS) (Spearman’s rho 0.72). It demonstrated acceptable responsiveness in patients with Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), as did the EQ-VAS. In patients with monoclonal gammopathy-related neuropathy and multifocal motor neuropathy, hardly any changes were seen over time.
Conclusion The IN-QoL questionnaire fulfils modern clinimetric requirements and correlates strongly with a patient’s self-assessment of their own quality of health, while also showing responsiveness in patients with GBS and CIDP. We propose using the IN-QoL and the EQ-VAS for assessing the QoL of patients with inflammatory neuropathies in future studies.
- Guillain-Barré syndrome (GBS)
- Chronic inflammatory demyelinating polyneuropathy (CIDP)
- IgM-monoclonal gammopathy of undetermined significance-related polyneuropathy (MGUSP)
- peripheral neuropathy
- multifocal motor neuropathy (MMN)
- Quality of Life (QoL)
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Contributors Study design: CGF, ISJM. Statistical analysis: THPD. Study recruitment: PeriNomS study group. Final report: THPD, ISJM, CGF.
Funding Study funding: GBS8CIDP Foundation International and Talecris Talents program. The study funding had no role in any of the following: design and conduct of the study, collection, management, analysis and interpretation of the data; and preparation, review or approval of the manuscript. Only financial support was provided to perform the study.
Competing interests CGF reports grants from the European Union’s Horizon 2020 research and innovation programme Marie Sklodowska-Curie grant for PAIN-Net, Molecule-to-man pain network (grant no. 721841), European Union 7th Framework Programme (grant n°602273), the Prinses Beatrix Spierfonds (W.OR12801), Grifols and Lamepro outside the submitted work. ISJM received funding for research from the Talecris Talents program, the GSB CIDP Foundation International, the European Union 7th Framework Programme (grant n°602273), Grifols and Lamepro. Furthermore, a research foundation at the University of Maastricht received honoraria on behalf of him for participation in steering committees of the Talecris ICE Study, LFB, CSL Behring, Novartis and Octapharma.
Ethics approval METC Erasmus MC.
Provenance and peer review Not commissioned; externally peer reviewed.
Collaborators A A Barreira, Brazil; D Bennett, UK; L H van den Berg, the Netherlands; P Y K Van den Bergh, Belgium; F Bombelli, France; V Bril, Canada; A Campanella, Italy; E A Cats, the Netherlands; D R Cornblath, USA; R Costa, France; G Devigili, Italy; P A van Doorn, the Netherlands; C G Faber, the Netherlands; J Franques, France; F Gallia, Italy; K C Gorson, USA; R D Hadden, UK; A F Hahn, Canada; R A C Hughes, UK; I Illa, Spain; H Katzberg, Canada; A J van der Kooi, the Netherlands; G Lauria, Italy; J-M Léger, France; R A Lewis, USA; M P T Lunn, UK; I S J Merkies, the Netherlands; S I van Nes, the Netherlands, E Nobile-Orazio, Italy; N C Notermans, the Netherlands; L Padua, Italy; J Pouget, France; L Querol, Spain; J Raaphorst, the Netherlands, MD; M M Reilly, UK; I N van Schaik, the Netherlands; M de Visser, the Netherlands.
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