Adverse effects of homeopathy, what do we know? A systematic review and meta-analysis of randomized controlled trials

Trine Stub; Frauke Musial; Agnete A Kristoffersen; Terje Alræk; Jianping Liu

doi:10.1016/j.ctim.2016.03.013

Adverse effects of homeopathy, what do we know? A systematic review and meta-analysis of randomized controlled trials

Complement Ther Med. 2016 Jun:26:146-63. doi: 10.1016/j.ctim.2016.03.013. Epub 2016 Mar 26.

Authors

Trine Stub¹, Frauke Musial², Agnete A Kristoffersen², Terje Alræk², Jianping Liu³

Affiliations

¹ The National Research Center in Complementary and Alternative Medicine (NAFKAM), Department of Community Medicine, Faculty of Health Science, UiT The Arctic University of Tromsø, 9037 Tromsø, Norway. Electronic address: trine.stub@uit.no.
² The National Research Center in Complementary and Alternative Medicine (NAFKAM), Department of Community Medicine, Faculty of Health Science, UiT The Arctic University of Tromsø, 9037 Tromsø, Norway.
³ Centre for Evidence-Based Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China.

PMID: 27261996
DOI: 10.1016/j.ctim.2016.03.013

Abstract

Objectives: Homeopathy is a popular treatment modality among patient, however there is sparse research about adverse effects of homeopathy. A concept unique for homeopathy, is homeopathic aggravation that is understood as a transient worsening of the patients' symptoms before an expected improvement occurs. From a risk perspective it is vital that a distinction between homeopathic aggravations and adverse effects is established. There is a lack of systematic information on how frequent adverse effects and homeopathic aggravations are reported in studies. Therefore, a systematic review and meta-analysis were performed.

Design and setting: Sixteen electronic databases were searched for Randomized Controlled Trials (RCTs). The searches were limited from the year 1995 to January 2011. Forty-one RCTs, with a total of 6.055 participants were included. A subtotal of 39 studies was included in the additional meta-analysis.

Results: A total of 28 trials (68%) reported adverse effects and five trials (12%) reported homeopathic aggravations. The meta-analysis (including six subgroup comparisons) demonstrated that no significant difference was found between homeopathy and control with OR 0.99, 95% CI 0.86-1.14, I(2)=54%. More than two third of the adverse effects were classified as grade 1 (68%) and two third were classified as grade 2 (25%) and grade 3 (6%) according to the Common Terminology Criteria for Adverse Effects. Homeopathic aggravation was classified as grade 1 (98%) and grade 3 (2%), suggesting that homeopathic aggravations were reported to be less severe than adverse effects. The methodological quality according to a method recommended in the Cochrane handbook for RCTs, was high.

Conclusion: Adverse effects including the concept of homeopathic aggravations are commonly reported in trials. The meta-analysis demonstrated that the proportion of patients experiencing adverse effects to be similar for patients randomized to homeopathic treatment compared to patients randomized to placebo and conventional medicine.

Keywords: Adverse effects; Adverse events; Homeopathic aggravations; Meta-analysis; Patient safety; Risk assessment; Systematic review.

Publication types

Meta-Analysis
Review
Systematic Review

MeSH terms

Homeopathy / adverse effects*
Humans
Patient Safety
Randomized Controlled Trials as Topic
Risk Assessment