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. 2019 Oct 23;2019(10):CD001417. doi: 10.1002/14651858.CD001417.pub4

Chung 2014.

Methods Double‐blind, placebo‐controlled, parallel‐group study
 2 treatment arms: 1 placebo, 1 topiramate
 Pre‐randomisation baseline period: 8 weeks
 Treatment period: 11 weeks
Participants A multicentre study (Argentina, Australia, Belgium, Canada, Chile, Germany, Greece, Hungary, India, Israel, New Zealand, Poland, Russia, South Africa, Spain, and USA)
 249 people randomised (all with drug‐resistant focal epilepsy): 125 to placebo and 124 mg to 200 mg per day topiramate
Age range: 18 to 75 years
Mean age: 37.6 years
 53% males
Other AEDs: 1 or more
 Median baseline seizure frequency/week: 2.7 for placebo group, 2.3 for topiramate group
Interventions 200 mg topiramate per day or placebo
Outcomes Primary outcome: median percentage reduction in weekly partial onset seizure frequency
Secondary outcomes:

  1. responder rate (≥ 50% reduction in seizure frequency)

  2. seizure freedom rate

  3. clinician‐reported Global Impression of Change (CGI‐C)

  4. patient‐reported Quality of Life in Epilepsy–Problems (QOLIE‐31‐P) survey

  5. adverse events

  6. safety and tolerability outcomes including laboratory parameters, neurology and physical examination, vital signs, and electrocardiography
Notes Trial sponsored by Upsher‐Smith Laboratories, Inc
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Quote: "Randomization by an independent statistician was generated using permuted blocks with a block size of 4 without stratification"
Allocation concealment (selection bias) Low risk Quote: "The interactive voice response group programmed the randomization schedule for investigators to dispense study drug."
Blinding (performance bias and detection bias) 
 All outcomes Low risk Quote: "matching placebo"
Blinding of participants and personnel (performance bias) 
 All outcomes Low risk Comment: it is likely that blinding was maintained
Blinding of outcome assessment (detection bias) 
 All outcomes Unclear risk Comment: specific details of outcome assessment blinding not provided
Incomplete outcome data (attrition bias) 
 All outcomes Low risk Comment: no concerns about missing data
Quote: "Efficacy analyses were performed using the intent‐to‐treat (ITT) population"
Selective reporting (reporting bias) Low risk Comment: protocol unavailable, but appears all expected and prespecified outcomes are reported
Other bias Low risk Comment: the study appears to be free of other sources of bias