Evidence map›Paper›PMID 18421484›Full record

SynthesisEuropean spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society2008

Imperfect placebos are common in low back pain trials: a systematic review of the literature.

L A C Machado, S J Kamper, R D Herbert, C G Maher, J H McAuley

Open access · bronzeAbstract readSystematic Review
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 2008. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 20 papers, 3 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
20citing papers in PubMed, 3 pooled it
2.2field-weighted citation impact, top 13% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

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.

2 · The registry

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.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

20 citing papers in PubMed, 3 syntheses or guidelines pooled it, 70 citations in OpenAlex.

  1. Pooled it
  2. Pooled it
  3. Guideline
  4. Trial
  5. Validation of a novel sham cervical manipulation procedure.The spine journal : official journal of the North American Spine Society · 2012
    Trial
  6. Trial
  7. Article
  8. Review
  9. Article
  10. Article
  11. Clinical Effectiveness and Efficacy of Chiropractic Spinal Manipulation for Spine Pain.Frontiers in pain research (Lausanne, Switzerland) · 2021
    Review
  12. Article
  13. Alpha-phase synchrony EEG training for multi-resistant chronic low back pain patients: an open-label pilot study.European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society · 2019
    Article
  14. Article
  15. Article
  16. Acupuncture for low back pain: an overview of systematic reviews.Evidence-based complementary and alternative medicine : eCAM · 2015
    Review
  17. Novel study designs to investigate the placebo response.BMC medical research methodology · 2011
    Review
  18. Article
  19. Article
  20. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors at 2 institutions in 2 countries.

L A C MachadoBack Pain Research Group, Musculoskeletal Division, The George Institute for International Health, Missenden Rd, P.O. Box M201, Camperdown, NSW, 2050, Australia. lmachado@george.org.au
S J Kamper
R D Herbert
C G Maher
J H McAuley
The George Institute for Global Health · AUGeorge Institute for Global Health · GB

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

The placebo is an important tool to blind patients to treatment allocation and therefore minimise some sources of bias in clinical trials. However, placebos that are improperly designed or implemented may introduce bias into trials. The purpose of this systematic review was to evaluate the adequacy of placebo interventions used in low back pain trials. Electronic databases were searched systematically for randomised placebo-controlled trials of conservative interventions for low back pain. Trial selection and data extraction were performed by two reviewers independently. A total of 126 trials using over 25 different placebo interventions were included. The strategy most commonly used to enhance blinding was the provision of structurally equivalent placebos. Adequacy of blinding was assessed in only 13% of trials. In 20% of trials the placebo intervention was a potentially genuine treatment. Most trials that assessed patients' expectations showed that the placebo generated lower expectations than the experimental intervention. Taken together, these results demonstrate that imperfect placebos are common in low back pain trials; a result suggesting that many trials provide potentially biased estimates of treatment efficacy. This finding has implications for the interpretation of published trials and the design of future trials. Implementation of strategies to facilitate blinding and balance expectations in randomised groups need a higher priority in low back pain research.

Indexed as

PlacebosRandomized Controlled Trials as TopicBack PainHumansResearch DesignPlacebos

Identifiers

PMID18421484
PMCPMC2443262
OpenAlexW2070624124

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.