Clinical Characteristics and Epidemiology of Isolated Dystonia: Results from a US Claims Analysis.

Abstract

Background: Dystonia is a rare, chronic movement disorder that is underrecognized, leading to delayed diagnosis. Epidemiological estimates and real-world characterization of isolated dystonia, occurring in the absence of other motor or neurological disorders, are limited.

Objectives: Estimate the US incidence and prevalence of isolated dystonia and characterize adults with isolated dystonia.

Methods: The retrospective study utilized a real-world claims database to identify an adult cohort (n = 20,951) with an index visit, defined as the first coded visit for dystonia, between January 2017-December 2024. Key outcomes included demographic and clinical characteristics of the adult cohort and US epidemiological estimates of dystonia without an identified secondary cause.

Results: The 2020-2023 period prevalence was 50.2 per 100,000, corresponding to an overall prevalence of 168,151 individuals with isolated dystonia in the US in 2023. Annual incidence (2020-2023) ranged from 31.8 to 41.5 per 100,000. The largest age group was 18-44 years (45.1%). Most adults were female (68.4%). High rates of anxiety (23%) and depression (15%) were observed. Focal dystonia was the most coded subtype (73%), and primary care providers were most associated with the index visit (30%). Adults had a mean of 8.5 physician office visits pre-index, increasing to 13.5 post-index.

Conclusions: This study defines an isolated dystonia cohort in the US based on real-world evidence and systematic exclusion of secondary causes of dystonia. Estimated prevalence is within range of prior epidemiological studies, and the cohort showed increased rates of comorbid psychiatric disorders. Methods are needed to resolve inconsistencies between clinical classification and coding practices.