Background: Neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) are rare disorders often seen in highly specialized services or tertiary centres. We aimed to assess if cohort characteristics depend on the origin of the referral catchment areas serviced by our centre (i.e. local, regional or national).
Methods: Retrospective cohort study using a national referral service database including local (Oxfordshire), regional (Oxfordshire and neighbouring counties), and national patients. We included patients with the diagnosis of NMOSD, seronegative NMOSD or MOGAD, followed at the Oxford Neuromyelitis Optica Service.
Results: We included 720 patients (331 with MOGAD, 333 with aquaporin-4 antibody (AQP4)-NMOSD, and 56 with seronegative NMOSD. The distribution of diagnoses was similar across referral cohorts. There were no significant differences in the proportion of pediatric onset patients, sex, or onset phenotype; more White AQP4-NMOSD patients were present in the local than in the national cohort (81 % vs 52 %). Despite no differences in follow-up time, more relapsing MOGAD disease was present in the national than in the local cohort (42.9 % vs. 24 %, p = 0.029).
Conclusion: This is the first study assessing the impact of potential referral bias in cohorts of NMOSD or MOGAD. The racial difference in the AQP4-NMOSD cohorts likely reflects the variation in the population demographics rather than a referral bias. The over representation of relapsing MOGAD patients in the national cohort probably is a true referral bias and highlights the need to analyze incident cohorts when describing disease course and prognosis. It seems reasonable therefore to compare MOGAD and NMOSD patients seen withing specialised centres to general neurology services, provided both use similar antibody assays.
Competing Interests: Declaration of competing interest Miguel Leal Rato has received support for attending meetings and/or travel grants from Sanofi, Novartis, Merck, and Boehringer Ingelheim. Anna Francis has received travel funding from Alexion. Eoin O'Sullivan has received honoraria from UCB and Roche. Leonora Fisniku has received support for scientific meetings and/or honorariums for advisory work from Biogen, Teva, Novartis, Sanofi, Merck and Roche. Cristopher Halfpenny has received honoraria and funding to attend meetings from Roche and Biogen. Roswell Martin has received support for attendance at conferences and speaker fees from Biogen, Roche, Eisai, Novartis and Teva. Jeremy Hobart has received consulting fees, honoraria, support to attend meetings, research support or clinical service support from Acorda, Bayer Schering, Biogen Idec, BMS, F. Hoffmann-La Roche, Janssen, Merck Serono, Novartis, Oxford PharmaGenesis, Sanofi-Genzyme, Teva. Waqar Rashid has received support for scientific meetings and courses and for advisory work from Biogen Idec, Merck, Novartis, Sanofi, Janssen and Bristol Myers and Squibb. Cheryl Hemingway reports grant support from the MRC, MS Society and Vasculitis UK; she serves as a consultant to Novartis, Biogen-IDEC, Roche, UCB, and Sanofi; she participated on data safety monitoring boards Wellcome SURE IDMC. Ruth Dobson works within the PNU, which is part funded by Barts Charity; has received honoraria for advisory boards and/or educational activities from Biogen, Teva, Sanofi, Merck, Janssen, Novartis, Sandoz and Roche; and research support from Biogen, Merck. Sithara Ramdas has received speaker honorarium from Roche and Novartis; advisory board honorarium from Sarepta, Argenx, Roche and Novartis. Maria Isabel Leite has received funding from the NHS National Specialised Commissioning Group for Neuromyelitis optica and the NIHR Oxford Biomedical Research Centre; and speaker honoraria or travel grants from Biogen Idec, Novartis, and the Guthy-Jackson Charitable Foundation. Jacqueline Palace has received support for scientific meetings and honorariums for advisory work from Merck Serono, Novartis, Chugai, Alexion, Roche, Medimmune, Argenx, Vitaccess, UCB, Mitsubishi, Amplo, Janssen; grants from Alexion, Argenx, Roche, Medimmune, Amplo biotechnology; patent ref P37347WO and licence agreement Numares multimarker MS diagnostics; she has shares in AstraZeneca; her group has been awarded an ECTRIMS fellowship and a Sumaira Foundation grant to start later this year; a Charcot fellow worked in Oxford 2019–2021; she acknowledges partial funding to the trust by Highly specialised services NHS England; she is on the medical advisory boards of the Sumaira Foundation and MOG Project charities; she is a member of the Guthy-Jackson Charitable Foundation; she is on the Board of the European Charcot Foundation, the steering committee of MAGNIMS, the UK NHSE IVIG Committee, she is chairman of the NHSE neuroimmunology patient pathway, an ECTRIMS Council member on the educational committee since June 2023, and she is on the ABN advisory groups for MS and neuroinflammation and neuromuscuscular diseases. Ruth Geraldes has received support for scientific meetings and courses from the EAN, Bayer, Biogen, Merck and Novartis; and honoraria for advisory work from Wolfson College. The remaining authors have no disclosures.
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