The frequency and characteristics of MS misdiagnosis in patients referred to the multiple sclerosis centre of Catalonia.

BACKGROUND: Multiple sclerosis (MS) misdiagnosis may cause physical and emotional damage to patients. OBJECTIVES: The objective of this study is to determine the frequency and characteristics of MS misdiagnosis in patients referred to the Multiple Sclerosis Centre of Catalonia. METHODS: We designed a prospective study including all new consecutive patients referred to our centre between July 2017 and June 2018. Instances of misdiagnosis were identified, and referral diagnosis and final diagnosis were compared after 1 year of follow-up. Association of misdiagnosis with magnetic resonance imaging (MRI) findings, presence of comorbidities and family history of autoimmunity were assessed. RESULTS: A total of 354 patients were referred to our centre within the study period, 112 (31.8%) with 'established MS'. Misdiagnosis was identified in eight out of 112 cases (7.1%). MRI identified multifocal white matter lesions, deemed non-specific or not suggestive of MS in all misdiagnosed cases. Patients with MS misdiagnosis had more comorbidities in general than patients with MS (p = 0.026) as well as a personal history of autoimmunity (p < 0.001). CONCLUSION: A low frequency of MS misdiagnosis was found in our clinical setting. Multifocal non-specific white matter lesions in referral MRI examinations and the presence of comorbidities, including a personal history of autoimmunity, seem to be contributing factors to misdiagnosis.