Proposed mechanisms for homeopathy are physically impossible

Working with patients' treatment expectations - what we can learn from homeopathy

The usual homeopathic remedy, "globules," does not contain any pharmacologically active ingredient. However, many patients and practitioners report beneficial effects of homeopathic treatment on various health outcomes. Experimental and clinical research of the last two decades analyzing the underlying mechanisms of the placebo effect could explain this phenomenon, with patients' treatment expectations as the predominant mechanism. Treatment expectations can be optimized through various factors, such as prior information, communication, and treatment context. This narrative review analyses how homeopathy successfully utilizes these factors. Subsequently, it is discussed what evidence-based medicine could learn from homeopathic practice to optimize treatment expectations (e.g., using an empathic, patient-centered communication style, deliberately selecting objects in practice rooms, or using clear treatment rituals and salient contextual stimuli) and thereby treatment effectiveness. Homeopathic remedy does not work beyond the placebo effect but is recommended or prescribed as an active treatment by those who believe in it. Thus, practitioners need to understand the manner in which homeopathy (as an example of inert treatment) works and are advised to reintegrate its underlying effective placebo mechanisms into evidence-based medicine. This promises to increase treatment efficacy, tolerability, satisfaction, and compliance with evidence-based treatments, and addresses the desires patients are trying to satisfy in homeopathy in an ethical, fully informed way that is grounded in evidence-based medicine.

An account of medical treatment, with a preliminary account of medical conditions

In this article, I present a philosophical account of medical treatment. In support of this account, I offer a suggestive account of medical conditions. The account of medical treatment uses three desiderata to demarcate treatment from non-treatment. Namely, a treatment should: (1) be describable by features that enable it to be standardized and characterized as a discrete intervention, (2) target a specific medical condition, and (3) have the possibility of being effective. The account of medical conditions underlies the second desideratum and attempts to tie medical conditions closely to biological dysfunction, while also including some conditions for which biological dysfunction is absent or its presence uncertain. I offer a simple typology of treatments and show how the accounts are relevant to treatment effectiveness, disease, placebos, contested treatments, and treatment standardization.

Homeopathy can offer empirical insights on treatment effects in a null field

OBJECTIVES

A "null field" is a scientific field where there is nothing to discover and where observed associations are thus expected to simply reflect the magnitude of bias. We aimed to characterize a null field using a known example, homeopathy (a pseudoscientific medical approach based on using highly diluted substances), as a prototype.

STUDY DESIGN AND SETTING

We identified 50 randomized placebo-controlled trials of homeopathy interventions from highly cited meta-analyses. The primary outcome variable was the observed effect size in the studies. Variables related to study quality or impact were also extracted.

RESULTS

The mean effect size for homeopathy was 0.36 standard deviations (Hedges' g; 95% confidence interval: 0.21, 0.51) better than placebo, which corresponds to an odds ratio of 1.94 (95% CI: 1.69, 2.23) in favor of homeopathy. 80% of studies had positive effect sizes (favoring homeopathy). Effect size was significantly correlated with citation counts from journals in the directory of open-access journals and CiteWatch. We identified common statistical errors in 25 studies.

CONCLUSION

A null field like homeopathy can exhibit large effect sizes, high rates of favorable results, and high citation impact in the published scientific literature. Null fields may represent a useful negative control for the scientific process.

Homeopathic medicinal products for preventing and treating acute respiratory tract infections in children

BACKGROUND

Acute respiratory tract infections (ARTIs) are common and may lead to complications. Most children experience between three and six ARTIs annually. Although most infections are self-limiting, symptoms can be distressing. Many treatments are used to control symptoms and shorten illness duration. Most treatments have minimal benefit and may lead to adverse events. Oral homeopathic medicinal products could play a role in childhood ARTI management if evidence for their effectiveness is established. This is an update of a review first published in 2018.

OBJECTIVES

To assess the effectiveness and safety of oral homeopathic medicinal products compared with placebo or conventional therapy to prevent and treat ARTIs in children.

SEARCH METHODS

We searched CENTRAL (2022, Issue 3), including the Cochrane Acute Respiratory Infections Specialised Register, MEDLINE (1946 to 16 March 2022), Embase (2010 to 16 March 2022), CINAHL (1981 to 16 March 2022), AMED (1985 to 16 March 2022), CAMbase (searched 16 March 2022), and British Homeopathic Library (searched 26 June 2013 - no longer operating). We also searched the WHO ICTRP and ClinicalTrials.gov (16 March 2022), checked references, and contacted study authors to identify additional studies.

SELECTION CRITERIA

We included double-blind randomised controlled trials (RCTs) or double-blind cluster-RCTs comparing oral homeopathy medicinal products with identical placebo or self-selected conventional treatments to prevent or treat ARTIs in children aged 0 to 16 years.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

In this 2022 update, we identified three new RCTs involving 251 children, for a total of 11 included RCTs with 1813 children receiving oral homeopathic medicinal products or a control treatment (placebo or conventional treatment) for ARTIs. All studies focused on upper respiratory tract infections (URTIs), with only one study including some lower respiratory tract infections (LRTIs). Six treatment studies examined the effect on URTI recovery, and five studies investigated the effect on preventing URTIs after one to four months of treatment. Two treatment and three prevention studies involved homeopaths individualising treatment. The other studies used predetermined, non-individualised treatments. All studies involved highly diluted homeopathic medicinal products, with dilutions ranging from 1 x 10^-4 to 1 x 10^-200. We identified several limitations to the included studies, in particular methodological inconsistencies and high attrition rates, failure to conduct intention-to-treat analysis, selective reporting, and apparent protocol deviations. We assessed three studies as at high risk of bias in at least one domain, and many studies had additional domains with unclear risk of bias. Four studies received funding from homeopathy manufacturers; one study support from a non-government organisation; two studies government support; one study was co-sponsored by a university; and three studies did not report funding support. Methodological inconsistencies and significant clinical and statistical heterogeneity precluded robust quantitative meta-analysis. Only four outcomes were common to more than one study and could be combined for analysis. Odds ratios (OR) were generally small with wide confidence intervals (CI), and the contributing studies found conflicting effects, so there was little certainty that the efficacy of the intervention could be ascertained. All studies assessed as at low risk of bias showed no benefit from oral homeopathic medicinal products, whilst trials at unclear or high risk of bias reported beneficial effects. For the comparison of individualised homeopathy versus placebo or usual care for the prevention of ARTIs, two trials reported on disease severity; due to heterogeneity the data were not combined, but neither study demonstrated a clinically significant difference. We combined data from two trials for the outcome need for antibiotics (OR 0.79, 95% CI 0.35 to 1.76; low-certainty evidence). For the comparison of non-individualised homeopathy versus placebo or usual care for the prevention of ARTIs, only the outcome recurrence of ARTI was reported by more than one trial; data from three studies were combined for this outcome (OR 0.60, 95% CI 0.21 to 1.72; low-certainty evidence). For the comparison of both individualised and non-individualised homeopathy versus placebo or usual care for the treatment of ARTIs, two studies provided data on short-term cure (OR 1.31, 95% CI 0.09 to 19.54) and long-term cure (OR 1.01, 95% CI 0.10 to 9.96; very low-certainty evidence). The studies demonstrated an opposite direction of effect for both outcomes. Six studies reported on disease severity but were not combined as they used different scoring systems and scales. Three studies reported adverse events (OR 0.79, 95% CI 0.16 to 4.03; low-certainty evidence).

AUTHORS' CONCLUSIONS

Pooling of five prevention and six treatment studies did not show any consistent benefit of homeopathic medicinal products compared to placebo on ARTI recurrence or cure rates in children. We assessed the certainty of the evidence as low to very low for the majority of outcomes. We found no evidence to support the efficacy of homeopathic medicinal products for ARTIs in children. Adverse events were poorly reported, and we could not draw conclusions regarding safety.

Assessing the magnitude of reporting bias in trials of homeopathy: a cross-sectional study and meta-analysis

OBJECTIVES

To assess the magnitude of reporting bias in trials assessing homeopathic treatments and its impact on evidence syntheses.

DESIGN

A cross-sectional study and meta-analysis. Two persons independently searched Clinicaltrials.gov, the EU Clinical Trials Register and the International Clinical Trials Registry Platform up to April 2019 to identify registered homeopathy trials. To determine whether registered trials were published and to detect published but unregistered trials, two persons independently searched PubMed, Allied and Complementary Medicine Database, Embase and Google Scholar up to April 2021. For meta-analyses, we used random effects models to determine the impact of unregistered studies on meta-analytic results.

MAIN OUTCOMES AND MEASURES

We report the proportion of registered but unpublished trials and the proportion of published but unregistered trials. We also assessed whether primary outcomes were consistent between registration and publication. For meta-analyses, we used standardised mean differences (SMDs).

RESULTS

Since 2002, almost 38% of registered homeopathy trials have remained unpublished, and 50% of published randomised controlled trials (RCTs) have not been registered. Retrospective registration was more common than prospective registration. Furthermore, 25% of primary outcomes were altered or changed compared with the registry. Although we could detect a statistically significant trend toward an increase of registrations of homeopathy trials (p=0.001), almost 30% of RCTs published during the past 5 years had not been registered.A meta-analysis stratified by registration status of RCTs revealed substantially larger treatment effects of unregistered RCTs (SMD: -0.53, 95% CI -0.87 to -0.20) than registered RCTs (SMD: -0.14, 95% CI -0.35 to 0.07).

CONCLUSIONS

Registration of published trials was infrequent, many registered trials were not published and primary outcomes were often altered or changed. This likely affects the validity of the body of evidence of homeopathic literature and may overestimate the true treatment effect of homeopathic remedies.

Opinions on Homeopathy for COVID-19 on Twitter

Homeopathy is a medical system originating in Germany more than 200 years ago. Based on prior investigations, mainstream health agencies and medical research communities indicate that there is little evidence that homeopathy can be an effective treatment for any specific health condition. However, it continues to be practiced as a popular form of alternative medicine in many countries, even during the ongoing COVID-19 pandemic. In this paper, we mine opinions on homeopathy for COVID-19 expressed in Twitter data. Our experiments are conducted with a dataset of nearly 60K tweets collected during a seven month period ending in July 2020. We first built text classifiers (linear and neural models) to mine opinions on homeopathy (positive, negative, neutral) from tweets using a dataset of 2400 hand-labeled tweets obtaining an average macro F-score of 81.5% for the positive and negative classes. We applied this model to identify opinions from the full dataset. Our results show that the number of unique positive tweets is twice that of the number of unique negative tweets; but when including retweets, there are 23% more negative tweets overall indicating that negative tweets are getting more retweets and better traction on Twitter. Using a word shift graph analysis on the Twitter bios of authors of positive and negative tweets, we observe that opinions on homeopathy appear to be correlated with political/religious ideologies of the authors (e.g., liberal vs nationalist, atheist vs Hindu). To our knowledge, this is the first study to analyze public opinions on homeopathy on any social media platform. Our results surface a tricky landscape for public health agencies as they promote evidence-based therapies and preventative measures for COVID-19.

Critical Evaluation of Specific Efficacy of Preparations Produced According to European Pharmacopeia Monograph 2371

European Pharmacopoeia monograph 2371 describes the production of homeopathic preparations. A specific efficacy of these preparations in high dilution levels is questionable in view of basic scientific principles. There is empirical evidence for such effects, for example in a Lemna-intoxication bioassay published 2010. To test the replicability and robustness of this bioassay, we conducted two experimental series (five independent blinded and randomised experiments each). The specimen of Lemna gibba L., clone-number 9352, were stressed in arsenic solution for 48 h (158 mg/L AsNa2HO4 (250 mg/L in series 2)), then grew in either As2O3 preparations produced according to Eu. Pharm. Monogr. 2371 or control solution. Comparing the area-related relative growth rate of day 3−9 (rgr 3−9) between treatment and control groups for each series showed differences that were not significant in series 1 (p = 0.10), significant in series 2 (p = 0.04) and significant in the pooled data of both series (p < 0.01). The effect direction (rgr 3−9 increase) was comparable to experiments of 2010, but the effect size was smaller, likely due to a changed light cycle. These results are not compatible with the hypothesis that the application of European Pharmacopoeia monograph 2371 results in pharmaceutical preparations without specific effects. Further studies are needed to investigate a potential mode of action explaining these effects.

Misinterpretations of P-values and statistical tests persists among researchers and professionals working with statistics and epidemiology

BACKGROUND

The aim was to investigate inferences of statistically significant test results among persons with more or less statistical education and research experience.

METHODS

A total of 75 doctoral students and 64 statisticians/epidemiologist responded to a web questionnaire about inferences of statistically significant findings. Participants were asked about their education and research experience, and also whether a 'statistically significant' test result (P = 0.024, α-level 0.05) could be inferred as proof or probability statements about the truth or falsehood of the null hypothesis (H₀) and the alternative hypothesis (H₁).

RESULTS

Almost all participants reported having a university degree, and among statisticians/epidemiologist, most reported having a university degree in statistics and were working professionally with statistics. Overall, 9.4% of statisticians/epidemiologist and 24.0% of doctoral students responded that the statistically significant finding proved that H₀ is not true, and 73.4% of statisticians/epidemiologists and 53.3% of doctoral students responded that the statistically significant finding indicated that H₀ is improbable. Corresponding numbers about inferences about the alternative hypothesis (H₁) were 12.0% and 6.2% about proving H₁ being true and 62.7 and 62.5% for the conclusion that H₁ is probable. Correct inferences to both questions, which is that a statistically significant finding cannot be inferred as either proof or a measure of a hypothesis' probability, were given by 10.7% of doctoral students and 12.5% of statisticians/epidemiologists.

CONCLUSIONS

Misinterpretation of P-values and statistically significant test results persists also among persons who have substantial statistical education and who work professionally with statistics.

An integrated perspective on transmutation of acute inflammation into chronic and the role of the microbiome

The Continuum theory and the Levels of Health theory were separately proposed to explain the myriad responses to treatment and understand the process of health and disease in an individual. In light of accumulating evidence on the intricate relationship between the human immune system and microbiome, an attempt is made in this article to connect these two theories to explain the transmutation of the efficiently responding immune system (through the acute inflammatory response and high fever) to one involved in a low-grade chronic inflammatory process (resulting in chronic disease). There is already enough evidence to demonstrate the role of the microbiome in all chronic inflammatory diseases. In this article, we discuss the mechanism by which subjecting a healthy person to continuous drug treatment for acute inflammatory conditions (at a certain time) leads to transmutation to chronic disease. Although this hypothesis requires further experimental evidence, it calls for a reconsideration of the manner in which we treat acute infectious diseases in the population.

Effects of Homeopathic Preparations of Mercurius corrosivus on the Growth Rate of Moderately Mercury-Stressed Duckweed Lemna gibba L

Background  A bioassay with severely mercury-stressed duckweed ( Lemna gibba L.) had revealed growth-inhibiting effects of homeopathically potentised mercury(II) chloride ( Mercurius corrosivus, Merc-c. ). We hypothesised that effects of potentised preparations are dependent on the stress level of the organisms used in the bioassay. The aim of the present investigation was to examine the response of duckweed to potentised Merc-c. at a lower stress level.

Methods  Duckweed was moderately stressed with 2.5 mg/L mercury(II) chloride for 48 hours. Afterwards plants grew in either Merc-c. (seven different potency levels, 24x–30x) or water controls (unsuccussed or succussed water) for 7 days. Growth rates of the frond (leaf) area were determined using a computerised image-analysis system for day 0–3 and 3–7. Three independent experiments with potentised Merc-c. and three systematic negative control experiments were performed. All experiments were randomised and blinded.

Results  Unsuccussed and succussed water did not significantly differ in their effects on duckweed growth rate. The systematic negative control experiments did not yield any significant effects, thus providing evidence for the stability of the experimental system. Data from the two control groups and the seven treatment groups ( Merc-c. 24x–30x) were each pooled to increase statistical power. Duckweed growth rates for day 3–7 were enhanced ( p  < 0.05) after application of Merc-c. compared with the controls. Growth rates for day 0–3 were not influenced by the homeopathic preparations.

Conclusions  Moderately mercury-stressed Lemna gibba L. yielded evidence of growth-enhancing specific effects of Merc-c. 24x–30x in the second observation period (day 3–7). This observation is complementary to previous experiments with severely mercury-stressed duckweed, in which a decrease in growth was observed in the first observation period (day 0–3). We hypothesise that the differing results are associated with the level of stress intensity (moderate vs. severe).

Homeopathic Preparations for Preventing and Treating Acute Upper Respiratory Tract Infections in Children: A Systematic Review and Meta-Analysis

BACKGROUND

Acute upper respiratory tract infections (ARTIs) are common and mostly self-limiting. A range of treatments are used with the aim to cure or treat symptoms, including widespread use of homeopathic treatments.

OBJECTIVE

To undertake a systematic review and meta-analysis of trials with the highest level of evidence, to establish the benefits and risks for oral homeopathic remedies used to treat and prevent ARTIs in children.

DATA SOURCES

MEDLINE, Embase, CINAHL, AMED, CAMbase, British Homeopathic Library, CENTRAL, WHO ICTRP and ClinicalTrials.gov registers to March 2018.

STUDY ELIGIBILITY, PARTICIPANTS, AND INTERVENTIONS

Double-blinded randomized trials in children, treated with oral homeopathic remedies versus placebo or conventional treatments for ARTI.

APPRAISAL AND SYNTHESIS METHODS

Studies were reviewed in duplicate for inclusion, data extraction, and risk of bias. Meta-analysis was performed on only 4 outcomes. Other outcomes were reported narratively.

RESULTS

Eight studies (1562 children) were included. Four studies examined treatment and 4 prevention of ARTIs. Four studies involved homeopaths individualizing treatment versus four with non-individualized treatments. Three studies had high risk of bias in at least 1 domain. All studies with low risk of bias showed no benefit from homeopathy; trials at uncertain and high risk of bias reported beneficial effects. Two individualized treatment studies (N = 155) did not show benefit on short-term or long-term cure. Prevention trials showed no significant outcomes: recurrence of ARTIs. No serious events were reported.

LIMITATIONS

Methodological inconsistencies and heterogeneity.

CONCLUSIONS

The effectiveness for homeopathic remedies for childhood ARTIs is not supported in higher quality trials.

Homeopathic Remedies in Psychiatric Disorders: A Meta-analysis of Randomized Controlled Trials

PURPOSE/BACKGROUND

Homeopathy is a complementary and alternative medicine. Conclusive evidence on the plausibility, efficacy, and safety of these treatments is not currently available. Nonetheless, homeopathic remedies (HRs) are widespread throughout the world and especially in mental disorders. The aim is to assess the efficacy of HRs in the treatment of mental disorders.

METHODS/PROCEDURES

We performed a Medline/Embase search for studies written in English and published from any date to October 23, 2018. All randomized controlled trials enrolling patients with any psychiatric disorder and comparing HR with placebo, no treatment, or other psychotropic drugs were included.

FINDINGS/RESULTS

A total of 212 studies were screened, 9 met all selection criteria and reported data on major depressive disorder (MDD) (n = 4), generalized anxiety disorder (n = 1), attention-deficit/hyperactivity disorder (n = 2), and premenstrual syndrome/dysphoric disorder (n = 2). Eight of 9 randomized controlled trials showed high risk of bias. Homeopathy showed greater efficacy in MDD compared with fluoxetine, and in premenstrual syndrome/dysphoric disorder compared with placebo, whereas no difference emerged between homeopathy and placebo in MDD and attention deficit/hyperactivity disorder.

IMPLICATIONS/CONCLUSIONS

Available data on homeopathy in psychiatric disorders are insufficient to support their use in clinical practice.

Establishing a taxonomy of potential hazards associated with communicating medical science in the age of disinformation

OBJECTIVES

Disinformation on medical matters has become an increasing public health concern. Public engagement by scientists, clinicians and patient advocates can contribute towards public understanding of medicine. However, depth of feeling on many issues (notably vaccination and cancer) can lead to adverse reactions for those communicating medical science, including vexatious interactions and targeted campaigns. Our objective in this work is to establish a taxonomy of common negative experiences encountered by those communicating medical science, and suggest guidelines so that they may be circumvented.

DESIGN

We establish a taxonomy of the common negative experiences reported by those communicating medical science, informed by surveying medical science communicators with public platforms.

PARTICIPANTS

142 prominent medical science communicators (defined as having >1000 Twitter followers and experience communicating medical science on social and traditional media platforms) were invited to take part in a survey, with 101 responses.

RESULTS

101 responses were analysed. Most participants experienced abusive behaviour (91.9%), including persistent harassment (69.3%) and physical violence and intimidation (5.9%). A substantial number (38.6%) received vexatious complaints to their employers, professional bodies or legal intimidation. The majority (62.4%) reported negative mental health sequelae due to public outreach, including depression, anxiety and stress. A significant minority (19.8%) were obligated to seek police advice or legal counsel due to actions associated with their outreach work. While the majority targeted with vexatious complaints felt supported by their employer/professional body, 32.4% reported neutral, poor or non-existent support.

CONCLUSIONS

Those engaging in public outreach of medical science are vulnerable to negative repercussions, and we suggest guidelines for professional bodies and organisations to remedy some of these impacts on front-line members.

The Bell Tolls for Homeopathy: Time for Change in the Training and Practice of North American Naturopathic Physicians

North American naturopathic medicine is a distinct form of practice that is woven into the larger fabric of integrative medicine; in a number of US states and Canadian provinces, naturopathic doctors enjoy a wide scope of practice, including the ability to make diagnoses, order tests, use medical technology, write prescription drugs, and perform minor surgeries. However, the basic premise of naturopathic medicine and its guiding principles-considering the whole person and supporting healthy lifestyle behaviors-is the unifying approach in clinical practice. In the 1970s, homeopathy-considered in many circles to be a hypothesis-driven, fringe form of alternative medicine-became embedded into the training and practice of North American naturopathic doctors. Since the earliest days of its theory (circa 1800), homeopathy has escaped, and continues to escape, biological plausibility; however, the persistence of this modality (and the insistence by both its consumers and practitioners that it provides benefit) speaks to the role of expectations, beliefs, values, agency, context effects, and the placebo-at-large. It is our contention that the progression of professional naturopathic medicine in the 21st century requires a major transition in how it approaches the subject of homeopathy. We propose that students should be encouraged to critically analyze the tenets of homeopathy, its lesser known history, and the idea of homeopathy as a biomedicine that simply awaits untold chemicophysical mechanisms. Furthermore, the modality of homeopathy should be incorporated into the larger context of placebo studies, narrative medicine, ethics, and psychotherapeutic techniques.

Reinterpreting homoeopathy in the light of placebo effects to manage patients who seek homoeopathic care: A systematic review

Homoeopathy is widespread, and users claim to benefit from it. However, clear evidence of its efficacy over placebo is not available to date. As a consequence, a social separation between homoeopathy users and mainstream medicine exists, exposing these patients to many risks. Our primary objective is to assess homoeopathy efficacy by systematically reviewing existing systematic reviews and meta-analyses and to systematically review trials on open-label placebo (OLP) treatments. A secondary objective is to understand if homoeopathy as a whole may be considered as a placebo treatment. PubMed/Medline, Embase, Google Scholar, and Cochrane Library were systematically searched for systematic reviews and meta-analyses on homoeopathy efficacy, and 61 studies were included. Same databases plus Journal of Interdisciplinary Placebo Studies (JIPS) were also systematically searched for randomised controlled trials (RCTs) on OLP treatments, and 10 studies were included. Databases were searched up to 24 February 2018. Two authors independently screened all retrieved articles and selected studies eligible for inclusion. The quality of reviews of included studies was evaluated with a dedicated NIH tool in the first review, whereas the risk of bias of trials of included studies was assessed with the specific Cochrane tool in the second review. Qualitative syntheses show that homoeopathy efficacy can be considered comparable to placebo, and that OLP treatments may be effective in some health conditions. Placebo effects like placebo itself, treatment context, physician-patient relationship, and other nonspecific factors can define the idea of placebo treatments, which may be effective in some conditions. If homoeopathy efficacy is comparable to placebo, and if placebo treatments can be effective in some conditions, then homoeopathy as a whole may be considered as a placebo treatment. Reinterpreting homoeopathy as a placebo treatment would define limits and possibilities of this practice. This perspective shift suggests a strategy to manage patients who seek homoeopathic care and to reconcile them with mainstream medicine in a sustainable way.

P-curve accurately rejects evidence for homeopathic ultramolecular dilutions

Background

P-curve has been proposed as a statistical test of evidential value. The distributions of sets of statistically significant p-values are tested for skewness. P-curves of true effects are right-skewed, with greater density at lower p-values than higher p-values. Analyses of null effects result in a flat or left-skewed distribution. The accuracy of p-curve has not been tested using published research analyses of a null effect. We examined whether p-curve accurately rejects a set of significant p-values obtained for a nonexistent effect.

Methods

Homeopathic ultramolecular dilutions are medicinal preparations with active substances diluted beyond Avogadro's number. Such dilute mixtures are unlikely to contain a single molecule of an active substance. We tested whether p-curve accurately rejects the evidential value of significant results obtained in placebo-controlled clinical trials of homeopathic ultramolecular dilutions.

Results

P-curve accurately rejected the evidential value of significant results obtained in placebo-controlled clinical trials of ultramolecular dilutions. Robustness testing using alternate p-values yielded similar results.

Conclusion

Our results suggest that p-curve can accurately detect when sets of statistically significant results lack evidential value.

Homeopathic medicinal products for preventing and treating acute respiratory tract infections in children

BACKGROUND

Acute respiratory tract infections (ARTIs) are common and may lead to complications. Most children experience between three and six ARTIs annually. Although these infections are self-limiting, symptoms can be distressing. Many treatments are used to control symptoms and shorten illness duration. Most have minimal benefit and may lead to adverse effects. Oral homeopathic medicinal products could play a role in childhood ARTI management if evidence for effectiveness is established.

OBJECTIVES

To assess the effectiveness and safety of oral homeopathic medicinal products compared with placebo or conventional therapy to prevent and treat acute respiratory tract infections in children.

SEARCH METHODS

We searched CENTRAL (2017, Issue 11) including the Cochrane Acute Respiratory Infections Specialised Register, MEDLINE (1946 to 27 November 2017), Embase (2010 to 27 November 2017), CINAHL (1981 to 27 November 2017), AMED (1985 to December 2014), CAMbase (searched 29 March 2018), British Homeopathic Library (searched 26 June 2013 - no longer operating). We also searched the WHO ICTRP and ClinicalTrials.gov trials registers (29 March 2018), checked references, and contacted study authors to identify additional studies.

SELECTION CRITERIA

Double-blind, randomised controlled trials (RCTs) or double-blind cluster-RCTs comparing oral homeopathy medicinal products with identical placebo or self-selected conventional treatments to prevent or treat ARTIs in children aged 0 to 16 years.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included eight RCTs of 1562 children receiving oral homeopathic medicinal products or a control treatment (placebo or conventional treatment) for upper respiratory tract infections (URTIs). Four treatment studies examined the effect on URTI recovery, and four studies investigated the effect on preventing URTIs after one to three months of treatment, followed up for the remainder of the year. Two treatment and two prevention studies involved homeopaths individualising treatment. The other studies used predetermined, non-individualised treatments. All studies involved highly diluted homeopathic medicinal products.We found several limitations to the included studies, in particular methodological inconsistencies and high attrition rates, failure to conduct intention-to-treat analysis, selective reporting, and apparent protocol deviations. We assessed three studies as at high risk of bias in at least one domain, and many had additional domains with unclear risk of bias. Three studies received funding from homeopathy manufacturers; one support from a non-government organisation; two government support; one was cosponsored by a university; and one did not report funding support.Methodological inconsistencies and significant clinical and statistical heterogeneity precluded robust quantitative meta-analysis. Only four outcomes were common to more than one study and could be combined for analysis. Odds ratios (OR) were generally small with wide confidence intervals (CI), and the contributing studies found conflicting effects, so there was little certainty that the efficacy of the intervention could be ascertained. All studies assessed as at low risk of bias showed no benefit from oral homeopathic medicinal products; trials at uncertain and high risk of bias reported beneficial effects.We found low-quality evidence that non-individualised homeopathic medicinal products confer little preventive effect on ARTIs (OR 1.14, 95% CI 0.83 to 1.57). We found low-quality evidence from two individualised prevention studies that homeopathy has little impact on the need for antibiotic usage (N = 369) (OR 0.79, 95% CI 0.35 to 1.76). We also assessed adverse events, hospitalisation rates and length of stay, days off school (or work for parents), and quality of life, but were not able to pool data from any of these secondary outcomes.There is insufficient evidence from two pooled individualised treatment studies (N = 155) to determine the effect of homeopathy on short-term cure (OR 1.31 favouring placebo, 95% CI 0.09 to 19.54; very low-quality evidence) and long-term cure rates (OR 0.99, 95% CI 0.10 to 9.67; very low-quality evidence). Adverse events were reported inconsistently; however, serious events were not reported. One study found an increase in the occurrence of non-severe adverse events in the treatment group.

AUTHORS' CONCLUSIONS

Pooling of two prevention and two treatment studies did not show any benefit of homeopathic medicinal products compared to placebo on ARTI recurrence or cure rates in children. We found no evidence to support the efficacy of homeopathic medicinal products for ARTIs in children. Adverse events were poorly reported, so conclusions about safety could not be drawn.

Homeopathic medicinal products for preventing and treating acute respiratory tract infections in children

BACKGROUND

Acute respiratory tract infections (ARTIs) are common and may lead to complications. Most children experience between three and six ARTIs each year. Although these infections are self limiting, the symptoms can be distressing. Many treatments are used to control symptoms and shorten the duration of illness. They often have minimal benefit and may lead to adverse effects. Oral homeopathic medicinal products could play a role in the treatment of ARTIs for children if evidence for effectiveness is established.

OBJECTIVES

To assess the effectiveness and safety of oral homeopathic medicinal products compared with placebo or conventional therapy to prevent and treat acute respiratory tract infections in children.

SEARCH METHODS

We searched CENTRAL (2017, Issue 11), which contains the Cochrane Acute Respiratory Infections Specialised Register, MEDLINE (1946 to 27 November 2017), Embase (2010 to 27 November 2017), CINAHL (1981 to 27 November 2017), AMED (1985 to December 2014), CAMbase (searched 29 March 2018), British Homeopathic Library (searched 26 June 2013 - no longer operating). We also searched the WHO ICTRP and ClinicalTrials.gov trials registers (29 March 2018), checked references, and contacted study authors to identify additional studies.

SELECTION CRITERIA

Double-blind, randomised controlled trials (RCTs) or double-blind cluster-RCTs comparing oral homeopathy medicinal products with identical placebo or self selected conventional treatments to prevent or treat ARTIs in children aged 0 to 16 years.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included eight RCTs of 1562 children receiving oral homeopathic medicinal products or a control treatment (placebo or conventional treatment) for upper respiratory tract infections (URTIs). Four treatment studies examined the effect on recovery from URTIs, and four studies investigated the effect on preventing URTIs after one to three months of treatment and followed up for the remainder of the year. Two treatment and two prevention studies involved homeopaths individualising treatment for children. The other studies used predetermined, non-individualised treatments. All studies involved highly diluted homeopathic medicinal products.We found several key limitations to the included studies, in particular methodological inconsistencies and high attrition rates, failure to conduct intention-to-treat analysis, selective reporting, and apparent protocol deviations. We assessed three studies as at high risk of bias in at least one domain, and many had additional domains with unclear risk of bias. Three studies received funding from homeopathy manufacturers; one reported support from a non-government organisation; two received government support; one was cosponsored by a university; and one did not report funding support.Methodological inconsistencies and significant clinical and statistical heterogeneity precluded robust quantitative meta-analysis. Only four outcomes were common to more than one study and could be combined for analysis. Odds ratios (OR) were generally small with wide confidence intervals (CI), and the contributing studies found conflicting effects, so there was little certainty that the efficacy of the intervention could be ascertained. All studies assessed as at low risk of bias showed no benefit from oral homeopathic medicinal products; trials at uncertain and high risk of bias reported beneficial effects.We found low-quality evidence that non-individualised homeopathic medicinal products confer little preventive effect on ARTIs (OR 1.14, 95% CI 0.83 to 1.57). We found low-quality evidence from two individualised prevention studies that homeopathy has little impact on the need for antibiotic usage (N = 369) (OR 0.79, 95% CI 0.35 to 1.76). We also assessed adverse events, hospitalisation rates and length of stay, days off school (or work for parents), and quality of life, but were not able to pool data from any of these secondary outcomes.There is insufficient evidence from two pooled individualised treatment studies (N = 155) to determine the effect of homeopathy on short-term cure (OR 1.31, 95% CI 0.09 to 19.54; very low-quality evidence) and long-term cure rates (OR 1.01, 95% CI 0.10 to 9.96; very low-quality evidence). Adverse events were reported inconsistently; however, serious events were not reported. One study found an increase in the occurrence of non-severe adverse events in the treatment group.

AUTHORS' CONCLUSIONS

Pooling of two prevention and two treatment studies did not show any benefit of homeopathic medicinal products compared to placebo on recurrence of ARTI or cure rates in children. We found no evidence to support the efficacy of homeopathic medicinal products for ARTIs in children. Adverse events were poorly reported, so conclusions about safety could not be drawn.

Comparison of veterinary drugs and veterinary homeopathy: part 2

Part 2 of this narrative review outlines the theoretical and practical bases for assessing the efficacy and effectiveness of conventional medicines and homeopathic products. Known and postulated mechanisms of action are critically reviewed. The evidence for clinical efficacy of products in both categories, in the form of practitioner experience, meta-analysis and systematic reviews of clinical trial results, is discussed. The review also addresses problems and pitfalls in assessing data, and the ethical and negative aspects of pharmacology and homeopathy in veterinary medicine.

Comparison of veterinary drugs and veterinary homeopathy: part 1

For many years after its invention around 1796, homeopathy was widely used in people and later in animals. Over the intervening period (1796-2016) pharmacology emerged as a science from Materia Medica (medicinal materials) to become the mainstay of veterinary therapeutics. There remains today a much smaller, but significant, use of homeopathy by veterinary surgeons. Homeopathic products are sometimes administered when conventional drug therapies have not succeeded, but are also used as alternatives to scientifically based therapies and licensed products. The principles underlying the veterinary use of drug-based and homeopathic products are polar opposites; this provides the basis for comparison between them. This two-part review compares and contrasts the two treatment forms in respect of history, constituents, methods of preparation, known or postulated mechanisms underlying responses, the legal basis for use and scientific credibility in the 21st century. Part 1 begins with a consideration of why therapeutic products actually work or appear to do so.

On the Viability of Conspiratorial Beliefs

Conspiratorial ideation is the tendency of individuals to believe that events and power relations are secretly manipulated by certain clandestine groups and organisations. Many of these ostensibly explanatory conjectures are non-falsifiable, lacking in evidence or demonstrably false, yet public acceptance remains high. Efforts to convince the general public of the validity of medical and scientific findings can be hampered by such narratives, which can create the impression of doubt or disagreement in areas where the science is well established. Conversely, historical examples of exposed conspiracies do exist and it may be difficult for people to differentiate between reasonable and dubious assertions. In this work, we establish a simple mathematical model for conspiracies involving multiple actors with time, which yields failure probability for any given conspiracy. Parameters for the model are estimated from literature examples of known scandals, and the factors influencing conspiracy success and failure are explored. The model is also used to estimate the likelihood of claims from some commonly-held conspiratorial beliefs; these are namely that the moon-landings were faked, climate-change is a hoax, vaccination is dangerous and that a cure for cancer is being suppressed by vested interests. Simulations of these claims predict that intrinsic failure would be imminent even with the most generous estimates for the secret-keeping ability of active participants—the results of this model suggest that large conspiracies (≥1000 agents) quickly become untenable and prone to failure. The theory presented here might be useful in counteracting the potentially deleterious consequences of bogus and anti-science narratives, and examining the hypothetical conditions under which sustainable conspiracy might be possible.