Epidemiology of myasthenia gravis in Denmark, Finland and Sweden: a population-based observational study.

BACKGROUND: Incidence and prevalence rates of myasthenia gravis (MG) vary considerably across studies, and mortality risk is rarely addressed. We examined the prevalence and incidence rates, mortality and factors associated with mortality with MG. METHOD: This was a registry linkage study based on nationwide health and administrative registries of Denmark, Finland and Sweden (populations of 5.9, 5.6 and 10.5 million, respectively). Patients with MG were identified based on International Classification of Diseases codes from inpatient and outpatient specialised care registries. Yearly prevalence, incidence and mortality rates in relation to the total background population were calculated from 2000 to 2020 (study period). The causes of death and factors associated with mortality were addressed separately. RESULTS: The overall incidence of MG was 1.34 (95% CI 1.27 to 1.41), 1.68 (95% CI 1.60 to 1.75) and 1.62 (95% CI 1.56 to 1.68) per 100 000, and the overall prevalence per 100 000 was 18.56 (95% CI 18.31 to 18.81), 20.89 (95% CI 20.62 to 21.16) and 23.42 (95% CI 23.21 to 23.64) in Denmark, Finland and Sweden, respectively. The overall standardised mortality ratio (SMR) was 1.32 (95% CI 1.23 to 1.42) among patients with MG in Denmark, 1.23 (95% CI 1.15 to 1.33) in Finland, and 1.20 (95% CI 1.14 to 1.26) in Sweden, with higher SMR observed in women than men. Annual incidence and prevalence increased over time, whereas the SMR remained stable. The most common causes of death were MG, chronic ischaemic heart disease and acute myocardial infarction. CONCLUSIONS: This population-based study from three Nordic countries highlights the need for improved care of patients with MG, especially young women.

The epidemiology and societal costs of myasthenia gravis in Norway: A non-interventional study using national registry data.

BACKGROUND AND PURPOSE: With the emergence of new treatment options for myasthenia gravis (MG), there is a need for information regarding epidemiology, healthcare utilization, and societal costs to support economic evaluation and identify eligible patients. We aimed to enhance the understanding of these factors using nationwide systematic registry data in Norway. METHODS: We received comprehensive national registry data from five Norwegian health- and work-related registries. The annual incidence and prevalence were estimated for the period 2013-2021 using nationwide hospital and prescription data. The direct, indirect (productivity losses) and intangible costs (value of lost life-years [LLY] and health-related quality of life [HRQoL]) related to MG were estimated over a period of 1 year. RESULTS: In 2021, the incidence of MG ranged from 15 to 16 cases per year per million population depending on the registry used, while the prevalence varied between 208.9 and 210.3 per million population. The total annual societal costs of MG amounted to EUR 24,743 per patient, of which EUR 3592 (14.5%) were direct costs, EUR 8666 (35.0%) were productivity loss, and EUR 12,485 (50.5%) were lost value from LLY and reduced HRQoL. CONCLUSION: The incidence and prevalence of MG are higher than previously estimated, and the total societal costs of MG are substantial. Our findings demonstrate that productivity losses, and the value of LLY and HRQoL constitute a considerable proportion of the total societal costs.

Economic and societal burden of myasthenia gravis in Denmark, Finland, and Sweden: A population-based registry study.

BACKGROUND AND PURPOSE: Health care resource utilization (HCRU) and the economic burden of myasthenia gravis (MG) are significant, but existing studies rarely include comprehensive nationwide data. We examined HCRU and direct and indirect costs associated with MG overall and by disease severity in Denmark, Finland, and Sweden. METHODS: Data were collected retrospectively from nationwide health and social care registries. All individuals ≥18 years of age with ≥2 International Classification of Diseases diagnoses of MG between 2000 and 2020 were included. HCRU, direct (inpatient and outpatient contacts, medication) and indirect costs (early retirement, sick leave, death), and associated factors were calculated. RESULTS: The full study cohort comprised 8622 people with MG (pwMG). Mean annual numbers of all-cause secondary health care contacts for pwMG were 3.4 (SD = 8.3), 7.0 (SD = 12.3), and 2.9 (SD = 3.9), with mean annual total costs of €12,185, €9036, and €5997 per person in Denmark, Finland, and Sweden, respectively. Inpatient periods, involving 77%-89% of study participants in the three countries, contributed most to direct costs, whereas the majority of indirect costs resulted from early retirement in Denmark and Finland, and sick leave periods in Sweden. Mean annual total costs were highest with very severe MG (€19,570-€33,495 per person across the three countries). Female sex and comorbidities, such as mental and behavioral disorders and severe infections, were also associated with higher total costs. CONCLUSIONS: This population-based study shows a high level of HCRU and a significant direct and indirect economic burden of MG across three Nordic countries, especially for severe forms of MG.