Director of Epidemiology Teva Pharmaceutical Industries Ltd Netanya, Israel
Background: Multiple system atrophy (MSA) is a rare neurodegenerative disorder characterized by autonomic failure, parkinsonism, cerebellar impairment, and corticospinal signs. No published literature is available on the prevalence of MSA in the US and incidence data are based on longstanding studies.
Objectives: To estimate the period prevalence and cumulative incidence of MSA in the US using a large claims database
Methods: This was a retrospective epidemiology study using MarketScan database. Period prevalence- individuals aged ≥30 years during the observation period (2016-2021) were identified as the denominator cohort. Numerator cohort were individuals who had MSA diagnosis during the observation period. MSA prevalence was also populated for each calendar year. Cumulative incidence- Denominator cohort included individuals who met the following inclusion criteria during each calendar year between 2017 and 2021: (1) ≥30 years old by index date (January 1st in the applicable calendar year); (2) have continuous enrollment during 1 year before index date and 1 year post the index date; (3) have no MSA diagnosis during 1 year before index date. Numerator cohort were individuals who had MSA diagnosis in 1 calendar year post index date. The primary endpoint is MSA diagnosis using ICD-10 codes G23.2, G23.8, G23.9, and G90.3 recorded during the observation period. Rates are expressed in number of cases per 100,000 persons. The prevalence of MSA cases was standardized to the US population aged ≥30 years based on 2021 US Census Bureau estimates.
Results: The prevalence of MSA was 41.7/100,000 persons aged ≥30 years in 2016-2021. The most frequently recorded diagnosis code was ICD-10- CM code G90.3 (53.1%). Individuals aged ≥65 years had the highest prevalence (164.5/100,000), while rates among younger age groups were lower (≤47.1/100,000). Prevalence rates among males were slightly lower compared to females (39.1 vs. 44.0/100,000). A gradual but very subtle decrease was observed in MSA prevalence from 2016 through 2020 (22.5 to 16.9/100,000) and increased slightly in 2021 (18.7/100,000). After standardization to the 2021 US population, the estimated prevalence of MSA in the US population aged ≥30 years was 64.9/100,000. The cumulative incidence in 2021 was higher in individuals aged ≥65 years than in younger age groups (65.3 vs. 6.5-14.1/100,000). The cumulative incidence was higher in male than in female aged 65 years and older (73.2 vs. 58.2/100,000). The cumulative incidence of MSA from 2017 through 2020 gradually decreased (20.3 to 12.7/100,000) and increased slightly in 2021 (16.0/100,000).
Conclusions: This study provides real-world evidence on the prevalence and incidence of MSA in the US population to better understand the need of medical care and treatment.