Real-World Adherence to OnabotulinumtoxinA Treatment for Spasticity: Insights From the ASPIRE Study

Objective: To identify baseline characteristics and treatment-related variables that affect adherence to onabotulinumtoxinA treatment from the Adult Spasticity International Registry (ASPIRE) study. Design: Prospective, observational registry (NCT01930786). Setting: International clinical sites. Participants: Adults with spasticity (N=730). Interventions: OnabotulinumtoxinA at clinician's discretion. Main Outcome Measures: Clinically meaningful thresholds used for treatment adherent (≥3 treatment sessions during 2-year study) and nonadherent (≤2 sessions). Data analyzed using logistic regression and presented as odds ratios (ORs) with 95% confidence intervals (CIs). Treatment-related variables assessed at sessions 1 and 2 only. Results: Of the total population, 523 patients (71.6%) were treatment adherent with 5.3±1.6 sessions and 207 (28.4%) were nonadherent with 1.5±0.5 sessions. In the final model (n=626/730), 522 patients (83.4%) were treatment adherent and 104 (16.6%) were nonadherent. Baseline characteristics associated with adherence: treated in Europe (OR=1.84; CI, 1.06-3.21; P=.030) and use of orthotics (OR=1.88; CI, 1.15-3.08; P=.012). Baseline characteristics associated with nonadherence: history of diplopia (OR=0.28; CI, 0.09-0.89; P=.031) and use of assistive devices (OR=0.51; CI, 0.29-0.90; P=.021). Treatment-related variables associated with nonadherence: treatment interval ≥15 weeks (OR=0.43; CI, 0.26-0.72; P=.001) and clinician dissatisfaction with onabotulinumtoxinA to manage pain (OR=0.18; CI, 0.05-0.69; P=.012). Of the population with stroke (n=411), 288 patients (70.1%) were treatment adherent with 5.3±1.6 sessions and 123 (29.9%) were nonadherent with 1.5±0.5 session. In the final stroke model (n=346/411), 288 patients (83.2%) were treatment adherent and 58 (16.8%) were nonadherent. Baseline characteristics associated with adherence: treated in Europe (OR=2.99; CI, 1.39-6.44; P=.005) and use of orthotics (OR=3.18; CI, 1.57-6.45; P=.001). Treatment-related variables associated with nonadherence: treatment interval ≥15 weeks (OR=0.42; CI, 0.21-0.83; P=.013) and moderate/severe disability on upper limb Disability Assessment Scale pain subscale (OR=0.40; CI, 0.19-0.83; P=.015). Conclusions: These ASPIRE analyses demonstrate real-world patient and clinical variables that affect adherence to onabotulinumtoxinA and provide insights to help optimize management strategies to improve patient care.