Truong 2008.
Study characteristics | ||
Methods | Randomised, double‐blind, placebo‐controlled Randomisation: participants were allocated sequential numbers and randomly assigned to one of the four treatment groups according to a computer‐generated randomisation schedule prepared before study initiation Setting: multicentre (USA only) Duration: 16 weeks |
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Participants | 123 participants enrolled (BtA group = 92; placebo group = 28) Placebo arm: 28 participants (18 dropouts: 64%); 19 participants were female and 9 were male; median age was 62 years (range: 45 to 82); ethnicity: 26 participants were Caucasian, 1 was African‐American, 1 was Asian, none were Hispanic, none were other ethnicity; mean duration of symptoms not stated; mean BDS score at baseline: not stated BtA(Dysport) 40 units/eye: 30 participants (7 dropouts: 23%); 21 participants were female and 9 were male; median age was 66 years (range: 35 to 82); ethnicity: 27 were Caucasian, 1 was African‐American, 1 was Asian, none were Hispanic, none were other ethnicity; mean duration of symptoms not stated; mean BDS score at baseline: not stated BtA(Dysport) 80 units/eye: 31 participants (6 dropouts: 19%); 24 participants were female and 7 were male; median age was 67 years (range: 45 to 80); ethnicity: 28 participants were Caucasian, 2 were African‐American, 1 was Asian, none were Hispanic, none were other ethnicity; mean duration of symptoms not stated; mean BDS score at baseline: not stated BtA(Dysport) 120 units/eye: 31 participants (4 dropouts: 13%); 25 participants were female and 6 were male; median age was 62 years (range: 33 to 91); ethnicity: 24 participants were Caucasian, 1 was African‐American, 1 was Asian, 2 were Hispanic, 2 participants were other ethnicity; mean duration of symptoms not stated; mean BDS score at baseline: not stated Inclusion criteria:
Exclusion criteria:
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Interventions | Participants were randomly assigned to one of 4 groups: placebo, 40 units/eye, 80 units/eye, 120 units/eye. The process was completed by an investigator not involved in treatment administration nor participant assessment. A total volume of 0.1 mL of Dysport or placebo was injected subcutaneously in each of the 6 injections sites in the region of the orbicularis oculi muscle. Each participant received only one treatment in each eye. BtA: Xeomin (incobotulinumtoxinA) Placebo: The reconstituted volume of placebo was equivalent to the reconstituted volume for the 120 units study group. Study drug preparation: Dysport (abobotulinumtoxinA) was prepared by reconstituting 500 units of freeze‐dried toxin with 2.5 ml of sodium chloride 0.9% to provide a concentration of 200 units/mL. A volume of reconstitute containing the appropriate number of units per study group (40, 80, or 120 units) was drawn up into a 1.0 mL syringe, which was filled with sodium chloride 0.9% up to a total volume of 0.6 mL EMG guidance: no information |
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Outcomes |
Primary outcome:
Secondary outcomes:
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Notes | This study was supported by funding from Ipsen Ltd. | |
Risk of bias | ||
Bias | Authors' judgement | Support for judgement |
Random sequence generation (selection bias) | Low risk | “Eligible patients were allocated sequential numbers before being randomly assigned to one of the four treatment groups according to a computer‐generated randomization schedule prepared before study initiation” |
Allocation concealment (selection bias) | Low risk | “A pack containing one vial of study medication (active treatment or placebo, identical in size and appearance) was allocated to each patient. Reconstitution of treatments was prepared by a third party, who was not involved with patient management or assessments” |
Blinding of participants and personnel (performance bias) All outcomes | Low risk | “A pack containing one vial of study medication (active treatment or placebo, identical in size and appearance) was allocated to each patient. Reconstitution of treatments was prepared by a third party, who was not involved with patient management or assessments. Investigators were blinded to the treatment dose and type of treatment throughout the study" |
Blinding of outcome assessment (detection bias) Objective outcomes | Unclear risk | Although all study personnel were stated to be blinded, the high proportion of dropouts in the placebo group (64%) suggests it was possible that the rating investigator identified the treatment group |
Blinding of outcome assessment (detection bias) Subjective outcomes | Unclear risk | Although all study personnel were stated to be blinded, the high proportion of dropouts in the placebo group (64%) suggests it was possible that the rating investigator identified the treatment group |
Incomplete outcome data (attrition bias) All outcomes | High risk | The large proportion of dropouts in the placebo group (64%) might have induced a clinically relevant bias |
Selective reporting (reporting bias) | Low risk | The expected outcomes that are usually evaluated in intervention trials for this condition were reported in this study |
Enriched population ‐ predominant enrolment of positive responders | Low risk | The inclusion and exclusion criteria do not make any reference to previous response to Botox |
Enriched population ‐ exclusion of poor responders | High risk | "Patients were not eligible for inclusion in the study if they had isolated levator dysfunction or eyelid apraxia" |
For‐profit bias | High risk | Study funding supported by Ipsen |
JRS: Jankovic Rating Scale
BSDI: Blepharospasm Disability Index