Clinical and Demographic Predictors of Optic Neuritis Subtype.

To determine which clinical features differentiate acute optic neuritis (ON) subtypes to support treatment decision-making in patients when the diagnostic work-up is incomplete or inconclusive. We performed a retrospective study at two academic centers. ON was classified as idiopathic/multiple sclerosis-associated (I/MS-ON; also known as "typical" ON) versus non-I/MS-ON (e.g. neuromyelitis optica; also known as "atypical" ON). Multiple linear regression models assessed the association between ON subtype and clinical features including: demographics, presence of optic disc edema, bilaterality (simultaneous ON involving both eyes), and baseline visual acuity (logMAR). Sensitivity analyses examined the impact of incomplete race/ethnicity data on subtype. Among 614 episodes (518 patients), most ON events (n = 440, 85%) were I/MS-ON. In univariate analyses, bilaterality (OR 6.67 [95%CI 3.7,11.11]), presence of optic disc edema (OR 2.22 [95%CI 1.32,3.70]), and age (OR 1.32 [95%CI 1.08,1.61] for each decade) were significantly associated with higher odds of having non-I/MS-ON compared to I/MS-ON. In multiple logistic regression modeling, each decade of life (OR 1.35 [95%CI 1.06,1.69]), bilaterality (OR 7.69 [95%CI 4.17,14.29]), and each point increase in baseline logMAR (OR 1.47 [95%CI 1.11,1.92]) were associated with increased odds of having non-I/MS-ON compared to I/MS-ON. In sensitivity analyses, age no longer significantly predicted ON subtype. When considering multiple clinical factors, bilateral simultaneous ON and worse baseline visual acuity were significantly associated with non-I/MS-ON. Older age may also be associated with non-I/MS-ON, but additional studies are needed. These observations may guide decision-making in patients with ON, in which diagnostic testing is incomplete or inconclusive.