Long-term safety and treatment discontinuation patterns of OnabotulinumtoxinA for post-stroke spasticity: a retrospective study

BACKGROUND: Post-stroke spasticity affects a significant proportion of stroke survivors and impairs quality of life. Repeated intramuscular injections of OnabotulinumtoxinA are widely used for spasticity management; however, long-term real-world outcomes remain underreported. This study aimed to evaluate the long-term safety and treatment continuation patterns, and to identify predictors of treatment discontinuation associated with repeated onabotulinumtoxinA treatment. METHODS: This retrospective, single-center study included 224 post-stroke patients treated with OnabotulinumtoxinA between 2012 and 2023. Inclusion criteria were a diagnosis of post-stroke spasticity, initiation of treatment before 2021, and at least three years of follow-up. Outcomes assessed included treatment continuation rates, reasons for discontinuation, dose trends, and predictors of treatment discontinuation. Logistic regression and repeated measures ANOVA were used for statistical analyses. RESULTS: Of the 224 patients, 94 (42%) continued treatment as of December 2023. Reasons for discontinuation included improvement and completion (n = 59, 45.4%), unknown reason (n = 39, 30.0%), Change of doctor or relocation (n = 13, 10.0%), insufficient efficacy (n = 13, 10.0%), switch to other treatment (n = 4, 3.1%), and adverse events (n = 2, 1.5%). Long-term treatment was associated with progressive dose escalation (p < 0.05).Logistic regression analysis showed that cerebral infarction was significantly associated with treatment completion due to improvement(p = 0.004), while a lower initial dose demonstrated a non-significant trend toward treatment completion (p = 0.051). CONCLUSIONS: Repeated onabotulinumtoxinA injections were not associated with unexpected safety concerns over long-term follow-up. Approximately 25% of patients discontinued treatment during the observation period, including cases documented as treatment completion due to clinical improvement. Stroke type was associated with treatment discontinuation patterns, supporting the importance of individualized long-term treatment planning.