Epidemiology of Progressive Supranuclear Palsy in Navarre, Spain: A Population‐Based Study

BACKGROUND: Epidemiological studies carried out on progressive supranuclear palsy (PSP) provide heterogeneous data. Our aim has been to analyze incidence, point prevalence, survival, and time to diagnosis of PSP in Navarre, a northern Spanish region. METHODS: This is a population-based observational retrospective study from 2010 to 2022. Data from various sources of health information were reviewed to identify all potential diagnoses of PSP, validated through medical records reviews. Patients were included if they fulfilled the 2017 Movement Disorder Society (MDS) criteria and were classified into the different PSP phenotypes. RESULTS: A total of 226 prevalent PSP cases were identified. Age-standardized point prevalence rate at January 1, 2023, was 7.52/100,000 inhabitants, and age-standardized annual incidence rate (IR) for the period was 2.41/100,000 person-years. PSP-Richardson syndrome (RS) phenotype showed significantly higher prevalence and incidence rates compared to PSP non-RS phenotypes. Joinpoint regression for overall incidence showed a significant increase until 2018 and thereafter a significant steep decline. Joinpoint regression for prevalence showed a statistically significant annual decline from 2018 onwards. Mortality rate experienced a peak in 2020. Median time to diagnosis was 37 months, and the median survival from clinical symptom onset was 89 months. PSP-RS was associated with reduced time to diagnosis and reduced survival compared to the PSP non-RS phenotypes. CONCLUSIONS: This study represents the first population-based epidemiological study of PSP in Spain and the first with application of the new MDS diagnostic criteria in Europe, providing detailed incidence, prevalence, and mortality data that are in accordance with other European studies.