Background: It is unclear whether the severity of and recovery from the initial demyelinating event (IDE) are recapitulated in subsequent multiple sclerosis (MS) relapses. We sought to identify the factors associated with relapse severity and recovery and to evaluate whether events have inherent severity or recovery.
Methods: Patients seen at the UCSF MS Clinic within 1 year of disease onset were identified from a prospective database. Ordinal logistic regression was used to analyze predictors of three-level categorizations of event severity and recovery.
Results: We identified 330 patients with MS or clinically isolated syndrome; 152 had a second event and 63 had a third event. Nonwhite and younger patients were at an increased risk of more severe demyelinating events. A severe prior event predicted a substantial increase in the odds of being above any given severity cutoff for a severe subsequent event (for second event severity, odds ratio [OR] = 5.62, 95% confidence interval [CI] [2.39, 13.26], p < 0.0001; for third event severity, OR = 6.74, 95% CI [1.67, 27.18], p = 0.007). Similarly, poor recovery of the IDE predicted poor second event recovery (OR = 5.28, 95% CI [1.95, 14.25], p = 0.001), while fair or poor second event recovery predicted about a 5- or 13-fold increase in the odds of poor third event recovery. A more severe event also predicted a substantial increase in the odds of poor recovery.
Conclusions: Patients with severe presentation and poor recovery at disease onset continue on a similar trajectory with subsequent demyelinating events. Whether genetic or other biologic factors are responsible for this pattern remains to be determined.