Epidemiologic and clinical features of multisystem atrophy: a population-based study in Navarre, Spain

Background: Epidemiological studies on multisystem atrophy (MSA) are scarce. Our aim has been to analyse 10-year incidence, point prevalence, survival, and the time to diagnosis of MSA in Navarre, a northern Spanish region.

Methods: This is a population-based observational retrospective study, from 2012 to 2021, which covered the population of Navarre (followed until 31 December 2021). Data from various sources of health information were reviewed in order to identify all potential diagnoses of MSA, that were validated from medical records. Patients were included if they fulfilled the new Movement Disorder Society criteria.

Results: We observed a crude average annual incidence rate (IR) of 0.49/100,000 person-years, with the highest occurring in the age group of 60-69 years. No significant IR differences by sex or subtype were observed. Point prevalence in December 2021 was 2.43/100,000 inhabitants. Joinpoint analysis for global incidence and prevalence experienced stable annual rates during the whole period, showing an upward trend for prevalence without a statistically significant slop. The median age at symptom onset was 65 years (range 47-76). The median time to diagnosis was 36 months, without statistically significant differences between sex, age at diagnosis or subtypes. Median time of survival from clinical onset was 7 years. Age of onset above 70 years and autonomic onset were associated with reduced survival.

Conclusions: This is the first population-based epidemiological study on MSA in Spain. It provides detailed incidence and prevalence data for MSA that may be useful for appropriate management of health resources.