Meta-Analysis: The Placebo Response in Modern Treatments for Cholestatic Pruritus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Igor Boechat Silveira, Leonardo Corrêa Süffert, Gustavo André Pedral Diniz Leite et al.
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In 30 seconds
This systematic review and meta-analysis examined placebo responses in randomized, placebo-controlled trials of ileal bile acid transporter inhibitors or PPAR agonists for cholestatic pruritus. Thirteen trials involving 548 participants were included. Across placebo groups, itch intensity improved during follow-up of up to 52 weeks; the pooled standardized mean change was -0.49 (95% CI, -0.72 to -0.27) overall and -0.57 (95% CI, -0.81 to -0.33) among participants with moderate-to-severe pruritus. Improvement varied by outcome instrument, and no evaluated trial-level moderators were statistically significant.
Key findings
- Pooled placebo response rates were 30.0% overall and 27.4% among participants with moderate-to-severe pruritus.
- For moderate-to-severe pruritus, NRS scores decreased by -1.62; the WI-NRS change of -0.65 was not statistically significant.
- PBC-40 itch-domain and overall scores decreased by -2.02 and -9.13, respectively, while 5-D Itch changes were non-significant.
- None of the evaluated trial-level moderators was statistically significant.
Why it matters
Placebo-associated improvement can influence the apparent size and interpretation of treatment effects in cholestatic-pruritus trials. The differing results across itch measures show that endpoint choice matters when comparing studies or assessing efficacy. Recognising these responses may also help researchers set realistic assumptions for future trial design.
What to keep in mind
The analysis is based on 13 trials and reports trial-level moderator analyses; no evaluated moderator was statistically significant.