(Research Hub Theater) Incidence of Dysphagia and Comorbidities in Patients with Cervical Dystonia, Analyzed by Botulinum Neurotoxin Treatment Exposure

Background and/or Objectives: Describe real-world incidence of dysphagia and other comorbidities in adults with cervical dystonia (CD) treated and not treated with botulinum neurotoxin (BoNT).

Design: Retrospective cohort study using longitudinal patient-level data from the Optum Market Clarity database.

Setting: >700 hospitals and >7000 clinics in the US.

Participants: Adults with ≥2 ICD-10 CD diagnoses ≥30 d apart during the study (1/1/2017-9/30/2021) and ≥180 d of continuous health plan enrollment before cohort entry date (CED; first CD diagnosis coding during study). Cohort 1: all patients with CD. Cohorts 2 and 3 (mutually exclusive): BoNT-exposed (date of BoNT injection in neck area +16 wk, excluding patients receiving BoNT 12 wk before CED) and BoNT-unexposed CD patients, respectively.

Interventions: BoNT

Main Outcome Measures: Incidence of dysphagia

Results: 81,884 CD patients in Cohort 1 (mean age 54 y, 68% female, 77% White), 19,244 in Cohort 2, and 61,154 in Cohort 3 were included. Relative to Cohort 3 (BoNT-unexposed), Cohort 2 (BoNT-exposed) had more patients in older age groups with comorbidities including chronic migraine and other neurologic disorders, but fewer males and African Americans. In Cohort 2, CD patients with continuous enrollment for ≥12 mo (73%) and ≥24 mo (53%) received BoNT for a mean±SD of 3.0±1.6 and 4.7±2.9 injection cycles, respectively. Reported dysphagia rates during the study were 13.7% (Cohort 1), 16.3% (Cohort 2), and 12.1% (Cohort 3). Across cohorts, incident dysphagia was more prevalent in patients with other dystonias, neurologic conditions, or baseline dysphagia. Patients diagnosed with dysphagia during follow-up were older with higher baseline comorbidity rates.

Conclusions: Real-world, heterogenous patients with CD may have occurrence of dysphagia whether exposed or not exposed to BoNT and which may be related to risk factors such as baseline dysphagia and other comorbidities. A limitation is that Cohort 2 may have included a higher proportion of older, sicker patients with more severe disease relative to Cohort 3.