Active Function Improvement with Repeated Injections of Botulinum Toxin A in Upper Limb Spasticity: A Longitudinal Analysis from the ULIS-III Study

Abstract

Improvement in active function (making it easier to use the limb) is a common goal following treatment of upper limb spasticity with botulinum toxin (BoNT-A). ULIS-III was a large international, observational, longitudinal study (N = 953) conducted in the context of usual clinical practice over two years. In this secondary post hoc analysis, we examine whether goals for improvement in active function were met over repeated injection cycles. Patients were selected if improved active function (AF) was a primary/secondary goal for at least one cycle of treatment (n = 286/953). They were assessed at the start and end of each cycle using the Goal Attainment T-score alongside the Arm Activity measure (ArmA). Serial changes and predictors of improvement were explored. Across eight cycles, there were 1167 injections for active function, 875/1998 (44%) AF goals were set and 493 (57%) of those goals were achieved. Patients continued to show significant improvement in AF (p < 0.001) for each injection at least up to three cycles, which is likely to be clinically significant, especially in patients with milder spasticity who were naïve to BoNT-A. No statistically significant predictors were confirmed on mixed effects modeling. Conclusions: Repeated BoNT-A continued to produce significant improvement in active function for at least three cycles, regardless of patient- or treatment-related factors in this cohort, but type II errors due to small numbers cannot be excluded.