Relapse risk factors in double seronegative neuromyelitis optica spectrum disorder: Insights from a multicenter study

To identify the risk factors associated with the relapse rate in patients with DSN-NMOSD.

This is a multicenter retrospective study of cases of DSN-NMOSD at the Mass General Brigham, the University of Sao Paulo, and Koc University. Patients were excluded if they had an alternative diagnosis. To examine the association of the different clinical and paraclinical factors on relapses, we calculated the incidence rate ratio (IRR) using a Poisson regression analysis.

A total of 35 relapsing DSN-NMOSD patients were analyzed. In a univariate Poisson regression analysis, non-Caucasian patients showed a higher rate of relapse (IRR: 1.58, 95 % CI 1.06-2.32; p=0.022) and simultaneous ON and transverse myelitis (TM) at onset resulted in a lower IRR of 0.04 (95 %CI 0.010-0.13; p <0.001). After adjusting for confounding factors, sex, race, laterality of ON, and use of disease-modifying therapy, age at onset at >32 years old was associated with a higher rate of relapses (IRR 1.82, 95 % CI 1.16-2.82; p = 0.008), while initial clinical manifestations of TM only (IRR 0.41, 95 % CI 0.22-0.74; p=0.004) and simultaneous ON and TM (IRR 0.04, 95 % CI 0.01-0.15; p <0.001) were linked to low relapse rates when compared to ON only.

Older adult onset (>32 years old) is linked to a higher relapse rate and patients presenting with TM only and simultaneous ON and TM at onset were found to be associated with a lower relapse rate.