Study design, materials and methods
A retrospective chart review was performed on all patients who received Botox injections from April 2013 to October 2017. Patients who received one injection of Botox were compared to those who received more than one. All data analysis was performed with SPSSv24.
We identified 175 patients who received at least one Botox injection. After the first injection, 86% (150/175) reported subjective symptom improvement. Of those who reported improvement, 54% (81/150) followed up for a second injection. Of those who reported no improvement 24% (6/25) also received a second injection. In total, 50% (87/175) returned for a second injection. Patients who received multiple injections were more likely to have perceived symptomatic improvement (p=0.034), and neurological disorders (p=0.011); those who received multiple injections were less likely to have side effects (p=0.027) (Figure 1). There was no significant difference in age, gender, BMI, or distance to clinic between these groups. Even among patients who reported improvement after Botox injection, compliance for subsequent injections was low (Figure 2).
Interpretation of results
Our data suggest that the presence of neurological disorders may influence the continuation of Botox therapy. Additionally, we found that despite reported symptomatic improvement, a significant proportion of patients did not follow up for repeat injection. This may be related to the presence of side effects which were less common in patients who chose to continue therapy.