Predictors of a placebo response in patients with hand osteoarthritis: post-hoc analysis of two randomized controlled trials

Jin Kyun Park, Se Han Ahn, Kichul Shin, Yun Jong Lee, Yeong Wook Song, Eun Bong Lee

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Placebo can have a significant therapeutic effect in patients with hand osteoarthritis (OA). This aim of the study is to identify factors associated with a clinically meaningful placebo response in patients with hand OA. Methods: This post-hoc analysis of two double-blind, placebo-controlled, randomized trials (RCTs) investigating the efficacy of GCSB-5 or diacerein as treatments for hand OA analyzed the efficacy of a placebo. Clinical and laboratory factors associated with a clinically meaningful response, defined as an improvement in the Australian/Canadian Osteoarthritis Hand Index (AUSCAN) pain score > 10 at 4 weeks relative to baseline, were identified. Results: The mean improvement in the AUSCAN pain score was − 6.0 ± 20.3, with marked variation between 143 hand OA patients (range: − 76.4 to 33.2). A clinically meaningful improvement was observed in 54 (37.8%) patients. Placebo responders had worse AUSCAN pain scores (55.7 ± 19.7 vs. 43.6 ± 21.6, p = 0.001) and a worse AUSCAN stiffness (68.2 ± 20.5 vs. 57.5 ± 24.5, p = 0.008) at baseline than non-responders. Improvements in pain correlated with the baseline pain level (Pearson r = − 427, p < 0.001). Structural joint changes such as tender, swollen, enlarged, or deformed joint counts did not differ between placebo responders and non-responders. In a multivariable analysis, only baseline AUSCAN pain was associated with a clinically meaningful placebo response (OR: 1.054, 95% CI [1.019–1.089], p = 0.002). Conclusions: High levels of pain at baseline are predictive of a clinically meaningful placebo response in patients with hand OA. Further studies are needed to optimize and utilize the benefit of placebo responses in patients with hand OA.

Original languageEnglish
Article number244
JournalBMC musculoskeletal disorders
Volume22
Issue number1
DOIs
StatePublished - Dec 2021

Keywords

  • Hand
  • Osteoarthritis
  • Placebo

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