Epidemiology of NMOSD in Sweden from 1987-2013: a nationwide population-based study

Objective: The objective was to report the yearly incidence rate and prevalence of neuromyelitis spectrum disorder (NMOSD) in Sweden and to investigate clinical characteristics, treatment and outcome.
Methods: We conducted a retrospective study of hospital case records of 294 individuals diagnosed with NMO (G36.0 ICD-10, 341.0 ICD-9) in the Swedish National Patient Register from 1987 to end of 2013 or detected by the presence of Aquaporin 4 IgG (AQP4) in serum during the study period. Ninety-two patients (51 NMO and 41 NMO spectrum-disorder) met the 2006 Wingerchuk criteria and were included in the study. Eleven Ten patients with an onset of NMO prior to 1987 and alive at the end of 2013 were included when estimating the prevalence.
Results: The average yearly incidence rate per 1,000,000 individuals increased significantly from 0.30 (CI: 0.19-0.41) between 1987-2006 to 0.79 (CI:0.55-1.03) between 2007-2013. The prevalence was 10.4 (CI:8.5-12.6) per 1,000,000 individuals as end of 20...