Phenotypic variants of progressive supranuclear palsy in a real-world dataset as identified by existing algorithms.

INTRODUCTION: Progressive supranuclear palsy (PSP) is a rare, relentlessly progressive, ultimately fatal neurodegenerative disease. Clinical phenotypes have been defined to describe observed heterogeneity in clinical characteristics of PSP patients; it is of interest to assess the potential of using datasets such as the one used in this study to determine predominant phenotypes of patients with PSP and enable epidemiological studies. We applied Movement Disorder Society (MDS)-PSP and Multiple Allocation eXtinction (MAX) algorithms for designating patients to PSP phenotypes using real-world data and describe the distribution of these phenotypes.

METHODS: Data were drawn from the Adelphi PSP Disease Specific Programme, a real-world cross-sectional study of neurologists and people living with PSP in the USA, France, Germany, Italy, Spain, and the UK. Patients were allocated to PSP phenotypes using MDS criteria and MAX Rules.

RESULTS: Data from 892 patients with PSP were evaluated (mean age: 68.9 years; 60.7 % male), and 816 (91 %) patients could be allocated to >1 phenotype (mean: 7.3 per patient). After applying MAX Rules, mean number of phenotypes per patient reduced to 1.0, with only 2 % of patients still allocated multiple phenotypes. While 42 % of patients were initially designated as PSP-Richardson syndrome (RS), this increased to 75 % when signs throughout the entire patient record were considered.

CONCLUSIONS: In the largest study done to date, these findings in real-world data confirm that applying of MAX Rules to MDS-PSP criteria can yield a predominant phenotype for majority of PSP patients and reinforce suggestions that PSP-RS becomes the predominant phenotype over time.