Although neuromyelitis optica (NMO) is known to be a more severe disease than relapsing-remitting multiple sclerosis (RRMS), few studies comparing both conditions in a single center have been done.
Methods: Comparison of our previously published cohort of 41 NMO patients with 177 RRMS patients followed in the same center, from 1994 to 2007.
Results: Mean age of onset was 32.6 for NMO and 30.2 for RRMS (p=0.2062) with mean disease duration of 7.4 years for NMO and 10.3 years for RRMS. Patients with NMO had a higher annualized relapse rate (1.0 versus 0.8, p=0.0013) and progression index (0.9 versus 0.6, p<0.0001), with more patients reaching expanded disability status scale (EDSS) 6.0 (39 versus 17%, p=0.0036). The odds ratio for reaching EDSS 6.0 and being deceased due to NMO in comparison to RRMS were, respectively, 3.14 and 12.15.
Conclusion: Patients with NMO have a more severe disease than patients with RRMS, including higher risk of dying of a demyelinating disease.