Prevalence of Progressive Supranuclear Palsy and Corticobasal Syndrome in Scotland

Introduction: We estimated the point prevalence of progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) at regional and national levels in Scotland, UK, as there are few high-quality prevalence studies of these conditions. Methods: Nationally, multiple methods of case ascertainment were used including clinician and nurse specialist referral, searches of ICD-10 diagnostic coding in routinely collected electronic health data (Scottish Morbidity Record), and patient self-referral. In one region, we also searched GP databases and unselected hospital correspondence. Cases were verified by clinical examination or medical record review. National and regional total and age-sex-stratified crude prevalence rates on December 31, 2018, were calculated. Results: The regional crude point prevalence was 4.28 per 100,000 (95% CI 2.90, 6.31) for PSP and 2.05 per 100,000 (95% CI 1.17, 3.59) for CBS. The national crude prevalence rates were lower due to the greater reliance on passive case ascertainment. There were no clear sex differences. At a national level, the peak crude prevalence rate for both PSP and CBS was in the 70-79 age group. Discussion: The prevalence rates of PSP and CBS were similar to previous estimates with little change over the past 20 years.