The impact of screening period pain inconsistency on placebo response in intra-articular knee osteoarthritis trials
Authors' conclusion
These findings extend earlier observations by revealing that not only the magnitude, but also the direction of screening pain fluctuation (worsening pain before randomization) predicts PR.
Study context
- Population
- Participants receiving intra-articular placebo in a Phase 2b knee osteoarthritis (OA) trialintra-articular placebo
- Participants
- 143 participants
- Comparison
- Screening Period Pain Inconsistency (SPPI) quartiles among placebo-treated participants
- Primary endpoint
- Change in WOMAC pain from baseline in the placebo group
- Follow-up
- Week 52
Methodological detailsdouble-blind, placebo-controlled, mixed model for repeated measures
- Double-blind
- Placebo-controlled
- Mixed model for repeated measures
Primary result
As reported in the abstract
Change in WOMAC pain across the trial period
LSM
−11.72
95% CI −17.43 to −6.02
aQ4 vs aQ1 · greater reduction with highest SPPI
LSM
−6.67
95% CI −12.47 to −0.86
dQ4 vs dQ1 · greatest placebo response (PR) with pain increasing during screening
Further findings
| Outcome | LSM (95% CI) |
|---|---|
| Change in WOMAC pain, directional quartiles · week 2dQ4 vs dQ1 | −7.92 (−13.65 to −2.19) |
Original publication
The impact of screening period pain inconsistency on placebo response in intra-articular knee osteoarthritis trials. Osteoarthritis Cartilage. Published 7 November 2025. doi:10.
Composed by AI from the published abstract and checked against it. How Briefs are made →