Nationwide prevalence and incidence study of neuromyelitis optica spectrum disorder in Denmark.

OBJECTIVES: To estimate the nationwide population-based incidence, prevalence, and geographical distribution of neuromyelitis optica (NMO) spectrum disorder (NMOSD) in Denmark based on the 2015 International Panel for NMO Diagnosis (IPND) criteria. METHODS: We conducted a multicentre, historically prospective study. Data were sourced from the Danish National Patient Registry, the Danish Multiple Sclerosis Registry, departments of neurology, and laboratories providing aquaporin-4 antibody test. Cases were selected based on the 2006 Wingerchuk and the 2015 IPND criteria and were individually validated by an expert panel. RESULTS: We confirmed NMO in 30 cases (2006 criteria) and NMOSD in 56 cases (2015 IPND criteria) between 2007 and 2014. Defined by the 2006 criteria, the incidence of NMO was 0.029 per 100,000 person-years (95% confidence interval [CI] 0.014-0.051), and the prevalence (aged 16 years and older) was 0.566 per 100,000 (95% CI 0.370-0.830). Based on the 2015 IPND criteria, the incidence of NMOSD was 0.070 per 100,000 person-years (95% CI 0.046-0.102), and the prevalence (aged 16 years and older) was 1.09 per 100,000 (95% CI 0.808-1.440), without regional differences. CONCLUSIONS: Our estimates of incidence and prevalence are similar to other Caucasian population-based studies using the 2015 IPND criteria. We found no geographical clustering in Denmark.

Social consequences of multiple sclerosis (1): early pension and temporary unemployment--a historical prospective cohort study.

Multiple sclerosis affects young and middle-aged people and often leads to physical and cognitive handicaps. There is a need for detailed knowledge of the social consequences of the disease. We aim here to describe the course of the working life and career of multiple sclerosis patients at the time of onset and thereafter, in terms of probability of early pension and income development. All 2538 patients with multiple sclerosis in Denmark with disease onset between 1980 and 1989, identified through the Danish MS-Registry, were included in this study. Twenty matched control persons per patient were randomly drawn from the civil registration system. Information on economic status was retrieved from Statistics Denmark. A survival analysis technique was used with onset as the starting point. We found that the probability of remaining without early pension was at 5 years 70% for patients and 97% for controls, and at 20 years 22% for patients and 86% for controls. Due to lower rates for early pension, gross income with time was lower in patients than controls. We conclude that multiple sclerosis seriously affects the economic life of multiple sclerosis patients, even within a few years of onset.