A randomized, double-blind, placebo-controlled study of the efficacy and safety of botulinum toxin type A in upper limb spasticity in patients with stroke.

OBJECTIVE

To study the efficacy and safety of botulinum toxin type A (BtxA) in the treatment of upper limb muscle spasticity, caused by stroke.

METHODS

This was a randomized, controlled trial. Patients received either placebo injections or a total of 1000 IU of BtxA (Dysport) into five muscles of the affected arm. Muscle tone was assessed using the Modified Ashworth Scale (MAS). Other outcome measures were the change in the joint range of motion (ROM), the Barthel index, pain score, goal attainment and the subjective evaluation of benefit by patients and investigators. The patients were assessed blind to randomization at baseline and 4, 8, 12 and 16 weeks after treatment.

RESULTS

Fifty nine patients were recruited and received treatment. One patient was lost to follow-up before the last scheduled visit of the study. The group of patients who received BtxA had a significant reduction in the summed MAS score at week 4 compared with the placebo group (P=0.004). The magnitude of benefit over the 16 week follow-up period was significantly reduced for the BtxA group in the wrist (P=0.004) and the finger joints (P=0.001) when compared with the placebo. There was no statistically significant difference between the groups in the joint ROM, muscle pain, goal-attainment or the Barthel index scores at week 4 of the study. At week 16, the BtxA group showed significantly greater improvement in the passive ROM at the elbow (P=0.036). The patients' global assessment of benefit at the end of the study showed that 16 (50%) patients in the placebo group had 'much improved' or had 'some improvement' compared with 24 (92.3%) patients in the BtxA group (P=0.007). The investigators' rating for the same item was 16 (50%) and 23 (88.4%) patients, respectively (P=0.002). Sixteen and twenty patients in the BtxA and placebo groups, respectively, had an adverse event. The most frequently reported adverse events were accidental injury, respiratory and urinary tract infections and muscle pain.

CONCLUSION

The findings of the present study suggest that treatment with BtxA in a dose of 1000 units reduces muscle tone in patients with post-stroke upper limb spasticity. This effect is sustained for at least 16 weeks. BtxA is safe in the dose used in this study. IMPORTANT NOTE: The authors wish to emphasize that the botulinum toxin preparation used in this study was Dysport (Ipsen Ltd) which has a different therapeutic equivalence from other commercially available product, Botox (Allergan Inc.).