Real-world analysis of botulinum toxin (BoNT) injections in post-stroke spasticity: Higher doses of BoNT and longer intervals in the early-start group.

Our primary objective was to compare early-start vs. late-start Botulinum toxin (BoNT) injections in post-stroke spasticity management. This is an IRB approved retrospective chart review of patients who were admitted for inpatient rehabilitation within 6 months after first-ever stroke between January 2014 and December 2018 and received BoNT injections within 15 months. The total dose and interval between consecutive injections were used as objective outcomes. 2367 stroke admissions were reviewed. 189 patients metinclusion criteria. 68 out of 189 patients received BoNT injections within 12 weeks after stroke (EARLY group). 20 patients in the EARLY group who received at least three cycles were included for analysis. Out of 189 patients, 47 patients were categorized into the Early- and Late-start subgroups each by time from stroke onset to first BoNT injection (1st and 4th quartiles of time distribution) for comparisons. In the EARLY group, the first interval (Mean (M) = 7.6 weeks, standard deviation (SD) = 2.14) was significantly shorter than the second interval (M = 23.7, SD = 10.41) and the third interval (M = 20.0, SD = 11.23; p < 0.05). The dose at the first cycle (M = 492 units, SD = 201.5) was significantly lower than the dose at the third cycle (M = 605, SD = 82.6). In comparison between the Early- and Late-start subgroups, the time to first BoNT injection was 6.4 weeks (range: 4.7-8.6) after stroke for the Early-start subgroup and 49.6 weeks (range: 27.4-62.3) after stroke for the Late-start subgroup. The subsequent intervals after the first injection were significantly longer in the Early-start subgroup (M = 23.1 weeks) than in the Late-start subgroup (M = 14.6 weeks) (p = 0.008). The average total dose of BoNT was significantly higher in the Early-start subgroup (M = 561.9 units, SD = 143.1) than the Late-start subgroup (M = 470.0, SD = 164.8) (p = 0.012). The findings showed that higher doses of BoNT were used in the Early-start group, and often resulted in longer intervals between subsequent injections than in the Late-start group.