Abstract
Objective
To quantify placebo effects and responses in randomized controlled trials (RCTs) on
neck pain and explore how they would influence the treatment of neck pain.
Data Sources
We searched MEDLINE (PubMed), EMBASE (Ovid), CINAHL (EBSCO), Physiotherapy Evidence
Database (PEDro), and World Health Organization International Clinical Trials Registry
Platform from the inception of August 15, 2021, to identify relevant RCTs.
Study Selection and Data Extraction
The abstracts and full texts of potential studies were independently screened, and
data extraction was also independently performed by 2 researchers. Scales of the score
measuring neck pain and the scores both at baseline and the endpoint were extracted.
Data Synthesis
A total of 60 RCTs were included. The mean improvement in the pain score after placebo
treatment was 15.65 (mean difference [MD]=-15.65, 95% confidence interval; CI [-19.19,
-12.12]; P<.05), which we defined as the placebo response. In the active groups, it was 25.91
(MD=-25.91, 95% CI [-29.15, -22.68]; P<.05), and in the no-treatment groups, it was 5.80 (MD=-5.80, 95% CI [13.28, 1.69];
P=.13). Using the 3 MDs from the 3 groups, the placebo effect was calculated to account
for 38.0% of the pain score improvement in the active group.
Conclusions
The pain scores of patients with neck pain were reduced after treatment with placebos,
but the magnitude of pain score reduction was not clinically significant enough. The
38.0% amount of pain score reduction in patients treated with active interventions
was caused by placebo. Interventions with considerable clinically significance for
neck pain were still required.
Keywords
List of abbreviations:
CI (confidence interval), MD (mean difference), RCT (randomized controlled trial)To read this article in full you will need to make a payment
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Article info
Publication history
Published online: November 20, 2022
Accepted:
October 26,
2022
Received in revised form:
October 25,
2022
Received:
October 3,
2022
Publication stage
In Press Journal Pre-ProofFootnotes
Supported by the National Natural Science Foundation of China (No. 81873197 and No. 72074161) and the Key Program of Sichuan Provincial Science and Technology Department, China (No. 2019YFSO194).
Disclosures: none.
Identification
Copyright
© 2022 by the American Congress of Rehabilitation Medicine.
