Diagnostic delay and misdiagnosis of symptoms reported by patients with multiple sclerosis participating in a research registry.

Background: Research cohort data suggest diagnostic delay in multiple sclerosis (MS) has diminished in tandem with MS diagnostic criteria revisions, yet other studies have not replicated this finding. Recent data indicate misdiagnosis of initial symptoms of MS is a frequent contributor to diagnostic delay.

Objectives: This survey study assessed diagnostic delay and misdiagnosis in an MS patient registry.

Methods: Participants completed the survey study between November 12, 2021, through December 22, 2021.

Results: There were 428 participants. Diagnostic delay was a median of 2.0 months (mean of 22.8 months, range: 0-32.9 years); 173/428 (40.4%) reported misdiagnosis of symptoms later attributed to MS, and this was associated with longer diagnostic delay (p < 0.001). Diagnostic delay decreased over time proximal to revisions to MS diagnostic criteria. 217/428 (50.7%) reported earlier symptoms retrospectively recognized as referable to MS that were not clinically evaluated, resulting in a diagnostic delay median of 5.4 years (mean 8.9 years, range: 0-47.4 years).

Conclusions: Diagnostic delay was prevalent and associated with frequent misdiagnosis of initial symptoms of MS and earlier unevaluated symptoms later attributed to MS. Studies tracing the diagnostic journey of patients with MS are needed to understand and prevent causes of diagnostic delay.