ArticleEpilepsia2025
Factors associated with placebo response rate in randomized controlled trials of antiseizure medications for focal epilepsy.
Article in Epilepsia, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
6 citing papers in PubMed.
- The impact of global recruitment and country income on placebo rates in inflammatory bowel disease clinical trials.Journal of Crohn's & colitis · 2026Article
- Patterns of seizure frequency reduction in clinical trial participants with lower baseline seizure frequency.Epilepsia · 2026Article
- Review
- Epilepsy and Placebo: A Literature Review.Neurologic clinics · 2026Review
- Inductive reasoning with large language models: A simulated randomized controlled trial for epilepsy.Epilepsy research · 2025Article
- Factors associated with placebo response rate in randomized controlled trials of antiseizure medications for focal epilepsy.Epilepsia · 2025Article
Corrections and comments
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Authors and funding
9 authors.
Funding
Abstract
objectiveRandomized controlled trials (RCTs) are necessary to evaluate the efficacy of novel treatments for epilepsy. However, there have been concerning increases in the placebo responder rate over time. To understand these trends, we evaluated features associated with increased placebo responder rate.
methodsUsing individual-level data from 20 focal-onset seizure trials provided by seven pharmaceutical companies, we evaluated associations with change in seizure frequency in participants randomized to placebo. We used multivariable logistic regression to evaluate participant and study factors associated with differing rates of 50% reduction in seizure frequency during blinded placebo treatment, as compared to pre-randomization baseline seizure frequency. In addition, we focused on the association of placebo responder rate with pre-randomization baseline seizure frequency and country of recruitment.
resultsIn the pooled analysis of 1674 participants randomized to placebo, a higher 50% responder rate (50RR) was associated with a shorter duration of epilepsy (p = .006), lower baseline seizure rate (p = .002), fewer concomitant antiseizure medications (p = .004), absence of adverse events (p < .001), more trial arms (p = .006), and geographic region (p < .001). Mixture modeling indicated a significantly higher 50RR in Bulgaria, Croatia, India, and Canada (42% in the higher group vs 22% in the lower group comprising all 40 other countries, p < 10 SIGNIFICANCE: These results can assist future RCTs in estimating the expected placebo responder rate, which may lead to more reliable power estimates. Higher placebo responder rate was associated with markers of less-refractory epilepsy. There were concerning significant differences in placebo responder rate by country and geographic region as well as an elevated placebo responder rate in participants with baseline seizure frequency close to the minimum eligibility criteria.
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Registered trials
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