COVID-19-related delays of botulinum toxin injections have a negative impact on the quality of life of patients with dystonia and spasticity: a single-center ambulatory care study

Background Botulinum toxin A (BoNT-A) is considered a safe and effective treatment for spasticity and dystonia. Individual interinjection intervals are critical for the maintenance of the effect. In Austria, BoNT outpatient clinics were shutdown from November to December 2020 during COVID-19 control measures, leading to rescheduling of BoNT-A injections. This survey aimed at investigating the influence of injection delays on symptoms, physical functioning, and quality of life (QoL) of the affected patients. Methods Between April and July 2021, 32 outpatients (21 females, mean age: 63.4 ± 12.1 years) treated ≥ 12 months at the BoNT outpatient clinic Horn-Allentsteig (Austria) and experienced ≥ 2 week injection delays, completed a structured face-to-face questionnaire. Results Indications were dystonia (34%), spasticity (63%), and hyperhidrosis (3%). Injections were delayed by 10 weeks (median, range: 2–15). Muscle cramps increased in 95% of patients with spasticity, muscle twitches in 91% of those with dystonia, and pain in 9% and 60% for dystonia and spasticity, respectively. Overall, 75% reported functional worsening, and deterioration in QoL by 62.6% ± 16.8 (mean ± SD). The impact on QoL correlated with the subjective global improvement induced by BoNT-A (Rs: 0.625; p