Early Use of Botulinum Toxin in Post-Stroke Spasticity Has the Potential to Prevent Post-Stroke Upper Limb Pain-A Secondary Analysis of the EUBoSS Randomised Controlled Trial.

Pain prevalence increased substantially over six months in post-stroke patients with severe upper limb impairment and spasticity.

• Pain prevalence at baseline was 29.0% (95% CI [20.1-37.9%])
• Pain prevalence increased to 63.4% (95% CI [54.0-72.9%]) at six months
• 93 participants (48F:45M) were included in the intention-to-treat analysis
• Participants were randomised at a median of 11 days post-stroke (IQR 8-19)

BoNTA treatment may prevent the development of pain at six months but not at three months post-stroke.

• Odds ratio for pain development at six months in BoNTA group was OR = 0.42 (95% CI [0.18 to 1.01])
• Odds ratio for pain at three months was OR = 0.57 (95% CI [0.25 to 1.32])
• The confidence interval at six months just crossed 1.0, suggesting a trend toward prevention without reaching conventional statistical significance
• BoNTA appeared less effective once pain was already established

BoNTA treatment was associated with significantly reduced analgesic use at six months compared to placebo.

• The odds ratio for being on at least one analgesic at six months in the BoNTA group was 0.35 (95% CI [0.14 to 0.87])
• This confidence interval did not cross 1.0, indicating a statistically significant reduction in analgesic use
• Differences in analgesic use between BoNTA and placebo groups were evaluated as part of the secondary analysis

Post-stroke upper limb pain is prevalent and challenging to manage once established in patients with severe upper limb impairment and spasticity.

• The study was conducted in a hyper/acute setting with randomisation at a median of 11 days post-stroke
• The study population had severe upper limb impairment and spasticity
• Early use of botulinum toxin can reduce spasticity and contracture development and has potential to prevent or reduce pain
• This was a secondary analysis of the EUBoSS randomised controlled trial

The authors conclude that further prospective studies are required to verify the hypotheses generated from this secondary analysis.

• This was a secondary analysis of the EUBoSS study, which limits the strength of conclusions
• Odds ratios with 95% confidence intervals were calculated as the primary statistical method
• The study used an intention-to-treat analysis with 93 participants
• The authors describe the findings as suggesting potential prevention of pain rather than confirmed efficacy