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

Abstract

ObjectivesTo 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.MethodsWe 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.ResultsWe 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.ConclusionsOur 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.

Epidemiology of neuromyelitis optica spectrum disorder in Denmark (1998–2008, 2007–2014)

“…Furthermore, in the relevant time period (2007–2014) patients with primary or secondary progressive forms of MS may not be followed by a neurology department. Moreover, in contrast to the previous study (Asgari et al, ), Papp et al () excluded patients who were not seen at a neurology department for the last 5 years. Papp et al () explained that this was unexpected in NMOSD, given the severity of this condition.…”

“…Moreover, in contrast to the previous study (Asgari et al, ), Papp et al () excluded patients who were not seen at a neurology department for the last 5 years. Papp et al () explained that this was unexpected in NMOSD, given the severity of this condition. However, patients who died may have been excluded.…”

“…A decade later, Papp and colleagues (Papp et al, ) studied the incidence and prevalence of NMOSD in Denmark with an 8‐year observation period (1 January 2007 to 31 December 2014). The author (Papp et al, ) obtained information from tertiary hospitals combined with laboratory databases on the determination of AQP4‐IgG to estimate the incidence and prevalence of NMOSD in Denmark. AQP4‐IgG measurement became available in December 2007 and therefore this data source was not available for the previous study (Asgari et al, ).…”

“…AQP4‐IgG measurement became available in December 2007 and therefore this data source was not available for the previous study (Asgari et al, ). The Danish MS registry was searched for ascertainment of cases (Papp et al, ). The number of MS cases with ON or TM was surprisingly low, with approximately 1.9% (300/15848) of patients alive (Papp et al, ).…”

“…The Danish MS registry was searched for ascertainment of cases (Papp et al, ). The number of MS cases with ON or TM was surprisingly low, with approximately 1.9% (300/15848) of patients alive (Papp et al, ). The incidence rate for MS in Denmark is estimated to be 12.3 per 100,000 in women and 6.1 per 100,000 in men (Koch‐Henriksen, Thygesen, Stenager, Laursen, & Magyari, ).…”