Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
, 19 (2), 159-66

Do Certain Countries Produce Only Positive Results? A Systematic Review of Controlled Trials

Comparative Study

Do Certain Countries Produce Only Positive Results? A Systematic Review of Controlled Trials

A Vickers et al. Control Clin Trials.


Objective: To determine whether clinical trials originating in certain countries always have positive results.

Data sources: Abstracts of trials from Medline (January 1966-June 1995).

Study selection: Two separate studies were conducted. The first included trials in which the clinical outcome of a group of subjects receiving acupuncture was compared to that of a group receiving placebo, no treatment, or a nonacupuncture intervention. In the second study, randomized or controlled trials of interventions other than acupuncture that were published in China, Japan, Russia/USSR, or Taiwan were compared to those published in England.

Data extraction: Blinded reviewers determined inclusion and outcome and separately classified each trial by country of origin.

Data synthesis: In the study of acupuncture trials, 252 of 1085 abstracts met the inclusion criteria. Research conducted in certain countries was uniformly favorable to acupuncture; all trials originating in China, Japan, Hong Kong, and Taiwan were positive, as were 10 out of 11 of those published in Russia/USSR. In studies that examined interventions other than acupuncture, 405 of 1100 abstracts met the inclusion criteria. Of trials published in England, 75% gave the test treatment as superior to control. The results for China, Japan, Russia/USSR, and Taiwan were 99%, 89%, 97%, and 95%, respectively. No trial published in China or Russia/USSR found a test treatment to be ineffective.

Conclusions: Some countries publish unusually high proportions of positive results. Publication bias is a possible explanation. Researchers undertaking systematic reviews should consider carefully how to manage data from these countries.

Similar articles

  • Full Publication of Results Initially Presented in Abstracts
    RW Scherer et al. Cochrane Database Syst Rev 11, MR000005. PMID 30480762.
    More than half of results from abstracts, and almost a third of randomized trial results initially presented as abstracts fail to be published in full and this problem do …
  • Acupuncture for Lateral Elbow Pain
    S Green et al. Cochrane Database Syst Rev (1), CD003527. PMID 11869671. - Review
    There is insufficient evidence to either support or refute the use of acupuncture (either needle or laser) in the treatment of lateral elbow pain. This review has demonst …
  • Acupuncture for Autism Spectrum Disorders (ASD)
    DK Cheuk et al. Cochrane Database Syst Rev (9), CD007849. PMID 21901712. - Review
    Current evidence does not support the use of acupuncture for treatment of ASD. There is no conclusive evidence that acupuncture is effective for treatment of ASD in child …
  • Acupuncture for Treating Acute Ankle Sprains in Adults
    TH Kim et al. Cochrane Database Syst Rev (6), CD009065. PMID 24953665. - Review
    The currently available evidence from a very heterogeneous group of randomised and quasi-randomised controlled trials evaluating the effects of acupuncture for the treatm …
  • Acupuncture for the Prevention of Tension-Type Headache
    K Linde et al. Cochrane Database Syst Rev 4, CD007587. PMID 27092807. - Review
    The available results suggest that acupuncture is effective for treating frequent episodic or chronic tension-type headaches, but further trials - particularly comparing …
See all similar articles

Cited by 146 PubMed Central articles

See all "Cited by" articles

Publication types

MeSH terms