RESUMO
BACKGROUND: The 2015 International Panel for neuromyelitis optica (NMO) spectrum disorders (NMOSD) diagnosis (IPND) criteria was recently proposed. However, because there are no studies evaluating application of the IPND criteria in Latin American populations, we aimed to assess whether these new criteria improve the diagnostic rate and reduce the time taken to make the diagnosis in a cohort of Latin American patients. METHODS: We reviewed medical records and applied both the 2006 and 2015 diagnostic criteria to all patients seen in four centers in Argentina, Brazil and Venezuela. Patients with multiple sclerosis (MS, n = 915) or other well-established central nervous system (CNS) inflammatory diseases were excluded. AQP4-ab status was measured using indirect immunofluorescence (23%) and cell-based assay (CBA, 77%). In addition, data on gender, ethnicity, age and symptoms at onset, relapses, neuroimaging and immunosuppressive therapy were collected. RESULTS: A total of 104 patients were classified as presenting NMOSD (2015 IPND). Of these, 64 patients (61.5%) fulfilled the 2006 NMO criteria (32 AQP4-ab positive, 17 AQP4-ab negative and 15 unknown). Thus, 40 new patients (38.5%) were classified as presenting NMOSD using the 2015 IPND criteria (33 AQP4-ab positive, 5 AQP4-ab negative and 2 unknown AQP4-ab status), with a median time taken to fulfill the 2015 NMOSD criteria (n = 104) of 1 month (95% CI: 0.6-1.3) and a median time taken to fulfill the 2006 NMO criteria (n = 64) of 18 months (95% CI: 9-26) (log-rank test: p < 0.0001). Females, with median age of 37 years, white ethnicity and recurrent course, predominated in all samples. Ninety-nine patients (95.1%) had at least 1 of the 3 major core clinical characteristics, of which optic neuritis (56.7%) was the most frequent symptom at disease onset. CONCLUSION: This study showed that there was a 62.5% increase in the rate of diagnosing NMOSD through the 2015 IPND criteria, in comparison with the 2006 NMO criteria, with a shorter median time to diagnosis.