Mult Scler. 2017 Oct 1:1352458517735191. doi: 10.1177/1352458517735191.
Sepúlveda M1, Aldea M2, Escudero D1, Llufriu S1, Arrambide G3, Otero-Romero S4, Sastre-Garriga J3, Romero-Pinel L5, Martínez-Yélamos S5, Sola-Valls N1, Armangué T6, Sotoca J7, Escartín A7, Robles-Cedeño R8, Ramió-Torrentà L8, Presas-Rodríguez S9, Ramo-Tello C9, Munteis E10, Pelayo R11, Gubieras L12, Brieva L13, Ortiz N14, Hervás M15, Mañé-Martínez MA16, Cano A17, Vela E18, Tintoré M3, Blanco Y1, Montalban X19, Graus F1, Saiz A1.
Abstract
BACKGROUND:
Population-based studies on neuromyelitis optica spectrum disorders (NMOSD) are limited, and it is unclear whether the rates have changed with the implementation of the new 2015 criteria.
OBJECTIVES:
To estimate the incidence and prevalence of NMOSD in Catalonia (Spain), using both the 2006 and the 2015 criteria.
METHODS:
In this clinic-based retrospective study, patients diagnosed with NMOSD between 2006 and 2015 were identified using multiple sources, including direct contact to all Catalan hospitals, identification of cases through the Catalan Health Surveillance System, and registry of antibodies to aquaporin-4 (AQP4-IgG) and myelin oligodendrocyte glycoprotein (MOG-IgG) in a reference laboratory. The incidence rate was calculated for the period 1 January 2006-1 January 2016 and prevalence for the date 1 January 2016.
RESULTS:
We identified 74 patients (by the 2015 criteria). Most patients were Caucasian (81%), and female (76%) with a median age at disease onset of 42 years (range, 10-76 years). In total, 54 (73%) patients were positive for AQP4-IgG, 11 (15%) double-seronegative, and 9 (12%) MOG-IgG-positive. Rates of incidence and prevalence (0.63/1,000,000 person-years and 0.89/100,000, respectively) were 1.5-fold higher than those reported by the 2006 criteria. Lowest rates were seen in children and elder people and highest in women and middle-aged people (40-59 years). The female predominance was lost in incident AQP4-IgG-seronegative children and AQP4-IgG-positive elder people. MOG-IgG and double-seronegativity contributed similarly but did not influence the long-term outcome.
CONCLUSION:
The new criteria increase the estimates, but NMOSD remains as a rare disease. The differences in age- and sex-specific estimates highlight the importance of the serologic classification.