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. 2014 Feb 5;2014(2):CD001908. doi: 10.1002/14651858.CD001908.pub3

Uthman 1998

Methods Randomised, double‐blind, placebo‐controlled, parallel‐group study. Four treatment arms: one PCB, three TGB. Participants randomly assigned using ratio of 3:2:3:2. Treatment period: 20 weeks (four‐week titration phase, 12‐week fixed‐dose treatment period, four‐week tapering period)
Participants Multi‐centre US study (21 centres) 297 participants with drug‐resistant partial epilepsy were randomly assigned (172 male), aged 12 to 77 years Participants already taking one to three AEDs, valproate allowed in combination with an enzyme‐inducing drug but not as monotherapy Median four‐weekly baseline complex partial seizure frequency was: PCB = 7.4; TGB 16 mg = 8.5; TGB 32 mg = 9.6; TGB 56 mg = 9.1 Cognitive effects were reported for a subset of 162 individuals
Interventions Group one: PCB
Group two: TGB 16 mg/d QID
Group three: TGB 32 mg/d QID
Group 4: TGB 56 mg/d QID
Outcomes

  1. 50% responder rates

  2. Treatment withdrawal

  3. Adverse effects

  4. Cognitive effects

  5. Quality of life
Notes From the 297 people randomly assigned to the double‐blind phase, five were excluded from the intention‐to‐treat analyses because no double‐blind assessments were done or their centres lacked participants in all treatment groups. All 297 people were evaluated for adverse events 54 people withdrew from the study: 13 receiving PCB; six receiving 16 mg TGB; 18 receiving 32 mg TGB and 17 receiving 56 mg TGB
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Unclear risk Ratio of 3:2:3:2 was used, no further details of sequence generation reported in text
Allocation concealment (selection bias) Low risk Used sequentially allocated sealed packages
Blinding (performance bias and detection bias) All outcomes Low risk Used identical packaging and medication
Incomplete outcome data (attrition bias) All outcomes Low risk Attrition rates reported and intention‐to‐treat analysis employed
Selective reporting (reporting bias) Low risk All outcomes reported in methods section were reported in text; however no protocol was available for comparison of outcomes

Abbreviations

  • AED = antiepileptic drug.
  • BID = twice daily.
  • ITT = intention‐to‐treat analysis.
  • PCB = placebo.
  • QID = four times daily.
  • TGB = tiagabine.
  • TPB = topiramate.
  • TID = three times daily.