Patients with neuromyelitis optica have a more severe disease than patients with relapsingremitting multiple sclerosis, including higher risk of dying of a demyelinating disease

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. Comparison of our previously published cohort of 41 NMO patients with 177 RRMS patients followed in the same center, from 1994 to 2007. 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