Bias (Epidemiology)

OBJECTIVE: The objective of this systematic review was to assess the effectiveness of yoga as a treatment option for asthma. METHOD: Seven databases were searched from their inception to October 2010. Randomized clinical trials (RCTs) and non-randomized clinical trials (NRCTs) were considered, if they investigated any type of yoga in patients with asthma. The selection of studies, data extraction, and validation were performed independently by two reviewers. RESULTS: Six RCTs and one NRCT met the inclusion criteria. Their methodological quality was mostly poor.

OBJECTIVE: To determine whether the conclusions of randomized controlled trials (RCTs) of yoga are more likely to be positive when they were conducted in India and/or when they are published in complementary and alternative medicine (CAM) specialty journals. METHODS: Medline/PubMed, Scopus, the Cochrane Library, IndMED, and the tables of content of yoga specialty journals not listed in medical databases were screened through February 2014 for RCTs comparing yoga interventions to non-yoga interventions.

BACKGROUND: A large proportion of mindfulness-based therapy trials report statistically significant results, even in the context of very low statistical power. The objective of the present study was to characterize the reporting of "positive" results in randomized controlled trials of mindfulness-based therapy. We also assessed mindfulness-based therapy trial registrations for indications of possible reporting bias and reviewed recent systematic reviews and meta-analyses to determine whether reporting biases were identified.

OBJECTIVE: To assess the efficacy, tolerability, and safety of hypnosis in adult irritable bowel syndrome by a meta-analysis of randomized controlled trials. METHODS: Studies were identified by a literature search of the databases Allied and Complementary Medicine Database, Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, PubMed, PsycINFO, and Scopus (from inception to June 30, 2013). Primary outcomes were adequate symptom relief, global gastrointestinal score, and safety.

OBJECTIVE: To determine whether any pre-clinical research in homoeopathy has been independently replicated. SEARCH STRATEGY: CISCOM was searched using the key words 'homeopathy' and 'basic research'. Further references were obtained from reviews, bibliographies, citation tracking and contact with experts. SELECTION CRITERIA: Studies comparing the effects of one or more homoeopathic medicines to no homoeopathic treatment on any live biological material apart from humans or animals under veterinary care. Research on intoxication and basophil degranulation was excluded.

Are cholesterol lowering drugs useful? Do they increase life expectancy? Do third generation oral contraceptives increase the risk of venous thromboembolism? Is there a worldwide decline in semen quality over the last 50 years? Do vitamin supplements improve your child's IQ? Does homeopathy work better than placebo? These questions illustrate some statistical problems and some bias encountered during clinical studies, which can lead to erroneous results. Type I and II errors, surveillance, prescription or publication bias as well as the healthy user effect are described.

At a time when scientists support Evidence-Based Medicine, the Parliament of Belgium has recently decided to recognize four alternative medicines, among which homeopathy. Whereas this discipline does not rely on any scientific basis, it appears to be popular, especially in general practice. The homeopaths have recently taken arguments from a meta-analysis published in 1997 in the Lancet of 89 placebo-controlled trials. This study indeed concluded that the results are not compatible with the hypothesis that the clinical effects of homeopathy are completely due to placebo.

The meta-analysis of homeopathy trials that appeared in the Lancet in 1997 seemed to endorse the experience of practitioners and patients that homeopathic medicines have specific clinically relevant effects.

BACKGROUND: Growing popularity of complementary and alternative medicine (CAM) in the public sector is reflected in the scientific community by an increased number of research articles assessing its therapeutic effects. Some suggest that publication biases occur in mainstream medicine, and may also occur in CAM. Homeopathy is one of the most widespread and most controversial forms of CAM. The purpose of this study was to compare the representation of homeopathic clinical trials published in traditional science and CAM journals.

A number of authors have recently discussed the possible role entanglement in homeopathy. Walach et al have published a homeopathic proving which they interpreted as demonstrating entanglement between placebo and verum groups in a proving. The lack of a 'run-in' period was a weakness of this trial. We present further results of our proving of Belladonna which show that subjects who reported symptoms during the placebo run-in period ('presentiment provers') were more likely to report symptoms during the treatment period.