Relationship of laryngeal botulinum toxin dosage to patient age, vitality, and socioeconomic issues.

OBJECTIVE: Chemical denervation with botulinum toxin A is the current standard of treatment for spasmodic dysphonia, but dosage is determined individually after a titration period that can take months to years. The objective of this study was to determine if age, body mass index (BMI), overall health, and socioeconomic factors were associated with a patient's optimal dose of botulinum toxin.

STUDY DESIGN AND METHODS: This retrospective chart review looked at 32 patients with stabilized doses of botulinum toxin. Age and BMI were obtained from patient charts, and overall health was assessed by the Short-Form 36 survey.

RESULTS: Analysis showed that BMI was positively correlated with botulinum toxin dose (r = 0.42, P = 0.02). Overall health showed a positive but nonsignificant association with dose, but subgroup analysis found that adductor spasmodic dysphonia (ADSD) patients without tremor had a significant positive correlation between overall health and dose (r = 0.50, P = 0.04), whereas tremor-only and mixed dystonia showed a negative nonsignificant correlation. Age was found to have no significant association with dose. Although socioeconomic factors were found to impact the number and frequency of injections, they had no significant impact on the ultimate dosage.

CONCLUSION: BMI and overall health are positively correlated with higher effective dose and may be useful in guiding clinicians during the titration period.