Clinical features and prognosis of late-onset neuromyelitis optica spectrum disorders in a Latin American cohort.

BACKGROUND: We aimed to assess the clinical, paraclinical, imaging and prognostic features of patients with late-onset neuromyelitis optica spectrum disorder (LO-NMOSD; ≥ 50 years at disease onset) LO-NMOSD, compared with early onset-NMOSD (EO-NMOSD, ≤ 49 years at disease onset), in Latin American (LATAM).

METHODS: We retrospectively reviewed the medical records of patients with NMOSD, as defined using the 2015 validated diagnostic criteria. We included patients from Argentina, Brazil and Venezuela. They were divided into: LO-NMOSD and EO-NMOSD and comparison among the groups were performed.

RESULTS: Among these 140 NMOSD patients, 24 (17.1%) were LO-NMOSD; 64% were positive for aquaporin-4 antibodies; and 41.5% of this population cohort was non-Caucasian. Severe disability [expanded disability status scale (EDSS) ≥ 6] at the last follow-up and presence of comorbidities were significantly associated with LO-NMOSD, compared with EO-NMOSD. LO-NMOSD patients had a shorter median time to EDSS ≥ 4 than EO-NMOSD patients (46 vs. 60 months; log-rank test p = 0.0006). Furthermore, we observed a positive correlation between age at onset and EDSS score at the last follow-up (Spearman r = 0.34, p < 0.0001).

CONCLUSION: LO-NMOSD patients from LATAM developed early severe disability, compared with EO-NMOSD. Therefore, age at onset could have important implications for the long-term prognosis of NMOSD patients.