Characteristics of IncobotulinumtoxinA Treatment for Limb Spasticity in a Real-World Setting: Dosing and Muscles Injected

Background and/or Objectives: IncobotulinumtoxinA is approved to treat upper limb spasticity (ULS) in adult and pediatric populations, and may be used off-label in some settings for lower limb spasticity (LLS). This study described incobotulinumtoxinA doses and muscles injected in a real-world setting for patients with limb spasticity (LS).

Design: The index visit was the first incobotulinumtoxinA encounter in this time frame. Prevalent and new users were included. Units and muscles injected were manually abstracted from clinical notes from encounters for incobotulinumtoxinA treatment. All analyses were descriptive.

Setting : This was a retrospective, observational study utilizing electronic health records (EHR).

Participants : Records from patients aged 2+ with evidence of LS and treatment with incobotulinumtoxinA from 1/1/2015-12/31/2022 were analyzed.

Interventions: N/A

Main Outcome Measures: N/A

Results: There were 315 patients identified (mean age=43 years, 55% male). Of those, 129 had ULS only, 84 had LLS only, and 102 had both. Approximately half of patients had prior incobotulinumtoxinA use. 980 encounters were analyzed with most patients (72%) contributing 3 or fewer visits. The most common muscles injected at the index visit were flexor carpi radialis, biceps, and flexor digitorum superficialis for patients with ULS only; hamstrings, gastronemius, and posterior tibialis for patients with LLS only; and hamstrings, flexor digitorum superficialis, and flexor carpi radialis for patients with both ULS and LLS. There were 509 unique muscle combinations identified. At the index visit, average dose for limb spasticity was 246 units (median=200) and average wasted units was 13 (median=0).

Conclusions: The doses of incobotulinumtoxinA and muscles injected for LS are very unique to the patient, indicating individualized care. Average doses were below the labeled maximum dose for incobotulinumtoxinA for most patient encounters regardless of the type of LS. Very little waste was recorded in clinical notes. The information gathered from the clinical notes is beyond what can be found in administrative claims or structured EHR.