[Treatment satisfaction in patients with cervical dystonia : Subgroup analysis of INTEREST-IN-CD-2]

Even though treatment guidelines recommend botulinum neurotoxin A (BoNT-A) as first line treatment for primary cervical dystonia (CD), there are only limited data on how BoNT-A-injections are administered in routine clinical practice.

This subgroup analysis evaluated patient satisfaction and symptom control under consideration of BoNT‑A treatment modalities in German and Austrian CD patients (DE/AT, n = 79) compared to the full international cohort (n = 995).

The INTEREST-IN-CD2 was a prospective, multicenter, longitudinal observational study. Course of treatment in adult primary CD patients under BoNT‑A treatment was assessed over a time period of 3 years. Primary outcome measure was the long-term satisfaction of patients with treatment, measured as maximum satisfaction between two consecutive injections as well as satisfaction at the time of reinjection.

Treatment satisfaction at the maximum effect was stable and comparably good in both populations during the study (82.3-92.7% and 85.0-89.9%). Satisfaction decreased with decreasing BoNT‑A effect at the end of the treatment interval: it was comparable at the start of the study in both groups (54.2% vs. 51.4%), decreased numerically in the DE/AT group to 32.7% but remained stable in the total population. Analysis of Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and Tsui scores did not reveal any substantial differences between the DE/AT subgroup and total cohort.

Overall, the study confirmed good clinical symptom control by BoNT‑A. The numerical differences in the current satisfaction seen in the comparison of DE/AT to the total cohort are possibly due to different proportions of BoNT‑A naïve patients in both groups, as they expressed different levels of satisfaction than previously treated patients.