Severity and impact of xerostomia in patients treated with botulinum toxin type b for cervical dystonia: Observations on the quality of life of patients with xerostomia

Abstract

Background: Although dry mouth (xerostomia) has been reported with botulinum toxin type B used as treatment for cervical dystonia, the impact of this adverse effect (AE) on patients' activities of daily living (ADLs) has not been assessed. t

Objective: The aim of this study was to examine the severity, duration, and impact of xerostomia in patients with cervical dystonia who reported this AE in routine clinical practice following treatment with botulinum toxin type B.

Methods: In this uncontrolled study, investigators at 5 study centers across the United States retrospectively identified patients who were diagnosed with cervical dystonia and had received ≥ 1 treatment with botulinum toxin type B injection and who had reported xerostomia, based on patients' charts. These patients were mailed a survey that included questions about their treatment history, disease severity, and xerostomia (severity, onset, duration, change with subsequent injections, and effects on dental and oral health), as well as an 8-item Patient Benefit Questionnaire (PBQ), which was designed to assess the impact of xerostomia symptoms on patients' ADLs.

Results: A total of 45 patients received a mean of 2.91 injections with botulinum toxin type B (mean dose per injection, 11,958 U), with a total of 131 injections. The mean severity of patient-rated xerostomia following the first injection of botulinum toxin type B was 3.88 on a scale of 1 (mild) to 5 (severe), and this rating did not change for patients who received subsequent injections (mean, 3.76). Following atypical injection of botulinum toxin type B, xerostomia began a mean (SD) of 4.82 (3.32) days later and persisted for a mean (SD) duration of 5.56 (3.57) weeks. The overall mean score on the 10-point PBQ prior to botulinum toxin treatment was 8.89, which decreased to 5.42 following botulinum toxin type B injection (lower scores indicate more severe xerostomia).

Conclusions: This study of patients with cervical dystonia suggests that patients who experience xerostomia following treatment with botulinum toxin type B injection, on average, rate their symptoms as moderate to severe and exhibit reduced scores on the PBQ-a questionnaire on which lower scores indicate greater negative impact of xerostomia on patients' ADLs.

Keywords: botulinum toxin; patient benefit questionnaire; xerostomia.