Do female and male patients with cervical dystonia respond differently to long-term botulinum neurotoxin therapy?

BACKGROUND

Idiopathic cervical dystonia (CD) affects more female than male patients. This sex-based influence on the clinical manifestation of CD may also affect outcomes after long-term BoNT therapy.

METHODS

To analyze the potential differential influence of sex on the efficacy of BoNT therapy, a cross-sectional study was conducted with 135 female and 85 male patients with idiopathic cervical dystonia. Demographic and treatment-related data were extracted from patient charts. The 24-item Cervical Dystonia Questionnaire (CDQ24), patients' self-assessment of CD severity (PAS), and the TSUI score were used as outcome measures. On the day of recruitment, blood samples were collected to analyze neutralizing antibody (NAB) formation using an ELISA, with confirmation by the mouse hemidiaphragm assay (MHDA) test.

RESULTS

Male patients had significantly ( < 0.02) lower mean age and age at symptom onset and received significantly ( < 0.02) higher BoNT doses per session. Female patients had significantly worse PAS and CDQ24 scores ( < 0.006), though the TSUI score showed no significant difference ( = 0.19). Despite receiving lower BoNT doses, female patients exhibited a significantly ( < 0.006) higher risk of NAB induction.

CONCLUSION

This reanalysis of previously published data reveals that female and male patients in this cohort were treated and responded differently to long-term BoNT therapy, a discrepancy that remained unnoticed by their treating physicians over more than 10 years of treatment.