BackgroundThe use of placebo interventions outside clinical trials is ethically, professionally and legally controversial. Little is known about the frequency and circumstances of placebo use in clinical practice. Our aim was to summarize the available empirical studies addressing these issues.MethodsWe searched PubMed and EMBASE from inception to July 2009 in order to identify cross-sectional surveys, qualitative or longitudinal studies among health care professionals, students or patients which investigated at least one of the following issues - frequency of placebo use or attitudes to, or motivations for, the use of placebo interventions. At least two reviewers extracted information on the study methods, participants and findings. Descriptive summaries were prepared in an iterative process by at least two reviewers per study.ResultsTwenty-two studies from 12 different countries met the inclusion criteria. Most studies had relevant shortcomings. The proportion of respondents reporting that they had applied 'pure' placebos (for example, saline injection) during their professional life varied between 17% and 80% among physicians and between 51% and 100% among nurses, but it seems that the actual frequency of such use seems to be rare. The use of 'impure' or 'active' placebos (for example, antibiotics for viral infections) is likely to be much more frequent. However, it is impossible to make a reliable estimation because there is no agreement of what an impure placebo might be. Studies using qualitative methods or asking participants to judge case examples suggest that motivations and attitudes towards placebo use are complex and health care providers are often faced with a dilemma.ConclusionsAlthough the available evidence is incomplete and confusing at times there can be little doubt that the prevalence of placebo use outside of clinical trials is not negligible and that views and attitudes on placebos use differ considerably among individuals, both health care professionals and patients. Further research is needed to clarify these issues.

IMPORTANCE When analyzing results of randomized clinical trials, the treatment with the greatest specific effect compared with its placebo control is considered to be the most effective one. Although systematic variations of improvements in placebo control groups would have important implications for the interpretation of placebo-controlled trials, the knowledge base on the subject is weak. OBJECTIVE To investigate whether different types of placebo treatments are associated with different responses using the studies of migraine prophylaxis for this analysis. DESIGN, SETTING, AND PARTICIPANTS We searched relevant sources through February 2012 and contacted the authors to identify randomized clinical trials on the prophylaxis of migraine with an observation period of at least 8 weeks after randomization that compared an experimental treatment with a placebo control group. We calculated pooled random-effects estimates according to the type of placebo for the proportions of treatment response. We performed meta-regression analyses to identify sources of heterogeneity. In a network meta-analysis, direct and indirect comparisons within and across trials were combined. Additional analyses were performed for continuous outcomes. EXPOSURE Active migraine treatment and the placebo control conditions. MAIN OUTCOMES AND MEASURES Proportion of treatment responders, defined as having an attack frequency reduction of at least 50%. Other available outcomes in order of preference included a reduction of 50% or greater in migraine days, the number of headache days, or headache score or a significant improvement as assessed by the patients or their physicians. RESULTS Of the 102 eligible trials, 23 could not be included in the meta-analyses owing to insufficient data. Sham acupuncture (proportion of responders, 0.38 [95% CI, 0.30-0.47]) and sham surgery (0.58 [0.37-0.77]) were associated with a more pronounced reduction of migraine frequency than oral pharmacological placebos (0.22 [0.17-0.28]) and were the only significant predictors of response in placebo groups in multivariable analyses (P = .005 and P = .001, respectively). Network meta-analysis confirmed that more patients reported response in sham acupuncture groups than in oral pharmacological placebo groups (odds ratio, 1.88 [95% CI, 1.30-2.72]). Corresponding analyses for continuous outcomes showed similar findings. CONCLUSIONS AND RELEVANCE Sham acupuncture and sham surgery are associated with higher responder ratios than oral pharmacological placebos. Clinicians who treat patients with migraine should be aware that a relevant part of the overall effect they observe in practice might be due to nonspecific effects and that the size of such effects might differ between treatment modalities.

BackgroundMetamizole is used to treat pain in many parts of the world. Information on the safety profile of metamizole is scarce; no conclusive summary of the literature exists.ObjectiveTo determine whether metamizole is clinically safe compared to placebo and other analgesics.MethodsWe searched CENTRAL, MEDLINE, EMBASE, CINAHL, and several clinical trial registries. We screened the reference lists of included trials and previous systematic reviews. We included randomized controlled trials that compared the effects of metamizole, administered to adults in any form and for any indication, to other analgesics or to placebo. Two authors extracted data regarding trial design and size, indications for pain medication, patient characteristics, treatment regimens, and methodological characteristics. Adverse events (AEs), serious adverse events (SAEs), and dropouts were assessed. We conducted separate meta-analyses for each metamizole comparator, using standard inverse-variance random effects meta-analysis to pool the estimates across trials, reported as risk ratios (RRs). We calculated the DerSimonian and Laird variance estimate T2 to measure heterogeneity between trials. The pre-specified primary end point was any AE during the trial period.ResultsOf the 696 potentially eligible trials, 79 trials including almost 4000 patients with short-term metamizole use of less than two weeks met our inclusion criteria. Fewer AEs were reported for metamizole compared to opioids, RR = 0.79 (confidence interval 0.79 to 0.96). We found no differences between metamizole and placebo, paracetamol and NSAIDs. Only a few SAEs were reported, with no difference between metamizole and other analgesics. No agranulocytosis or deaths were reported. Our results were limited by the mediocre overall quality of the reports.ConclusionFor short-term use in the hospital setting, metamizole seems to be a safe choice when compared to other widely used analgesics. High-quality, adequately sized trials assessing the intermediate- and long-term safety of metamizole are needed.

To collect data on the use of placebo interventions by GPs in Germany.Methods. A questionnaire was mailed to 400 randomly selected GPs in Bavaria. Non-responders were reminded by telephone after 4 weeks and were given a second copy of the questionnaire after a further 3 weeks. Results. In all, 208 completed questionnaires were returned. The majority of GPs (88%) have used a placebo at least once in their practice; 45% have used pure placebos, such as saline injections and sugar pills, at least once last year; the median frequency of use was 5 [interquartile range (IQR), 2-10]. The use of impure placebos during the past year was more common: 76% of GPs have used impure placebos, i.e. medical interventions that have pharmacological or physical activity but have no intrinsic effect (e.g. pharmacological or physical action) on the patient's disease or its symptoms, with a median frequency of 20 times per year (IQR, 10-50). The main reason for the use of placebo was a possible psychological effect, followed by the expectation of patients to receive a treatment. For the majority of GPs placebo interventions were ethically justified if they were used for a possible psychological effect.Conclusions. Placebo interventions are a widely accepted part of medical treatment in German general practices and are used primarily for their psychological effects. Impure placebos are used much more frequently than pure placebos.

Background: Placebo interventions can have meaningful effects for patients. However, little is known about the circumstances of their use in clinical practice. We aimed to investigate to what extent and in which way Swiss primary care providers use placebo interventions. Furthermore we explored their ideas about the ethical and legal issues involved.

This article reviews the role of placebo interventions and placebo effects in clinical practice. We first describe the relevance of different perspectives among scientists, physicians and patients on what is considered a placebo intervention in clinical practice. We then summarize how placebo effects have been investigated in randomized controlled trials under the questionable premise that such effects are produced by placebo interventions. We further discuss why a shift of focus from the placebo intervention to the overall therapeutic context is necessary and what research methods can be used for the clinical investigation of the relevance of context effects. In the last part of the manuscript, we discuss why placebo or context effects are seen as positive in clinical practice when they are associated with active treatments, while placebo interventions pose major ethical and professional problems and have to be avoided.

BackgroundFew studies have investigated whether patients and physicians differ in their attitudes regarding placebo interventions in medical practice. AimTo compare the proportions of patients and physicians who would accept therapies that do not work through specific pharmacological or physiological action but by enhancing self-healing capacities and by exploiting contextual factors. Design of studySurvey of a random sample of GPs and patients consecutively attending in primary care practices. SettingFour hundred and seventy-seven patients and 300 GPs from primary care practices of the Canton Zurich of Switzerland were approached. MethodTwo questionnaires on responders' attitudes regarding non-specific therapies. ResultsThe response rates were 87% for patients and 79% for GPs. Eighty-seven per cent of patients and 97% of GPs thought that physical complaints can get better by believing in the effectiveness of the therapy. Overall there was more support for placebo interventions among patients than among GPs, yet 90% of the physicians admitted to actively proposing treatments intended to take advantage of non-specific effects. Seventy per cent of the patients wanted to be explicitly informed when receiving a non-specific intervention, whereas physicians thought this was the case for only 33% of their patients. Fifty-four per cent of patients would be disappointed when learning they had unknowingly been treated with pure placebo ('sugar pill'), while only 44% would feel that way after treatment with impure placebo (for example, herbal medicine). ConclusionGPs rather underestimate the openness of their patients to non-specific therapies. However, patients want to be appropriately informed. Developing specific professional standards could help physicians to harness the 'power of the placebo', while remaining authentic and credible.

BackgroundPlacebos play an important role in clinical trials and several surveys have shown that they are also common in daily practice. Previous research focused primarily on the frequency of placebo use in outpatient care. Our aim was to explore physicians' views on the use of placebos in daily practice, whereby distinction was made between pure placebos (substances with no pharmacological effect, e.g. sugar pills) and impure placebos (substances with pharmacological effect but not on the condition being treated, e.g. antibiotics in viral infections or vitamins).MethodsWe performed semi-structured interviews with a sample of twelve primary care physicians (PCPs). The interview addressed individual definitions of a placebo, attitudes towards placebos and the participants' reasons for prescribing them. The interviews were transcribed and analysed using qualitative content analysis.ResultsThe definition of a placebo given by the majority of the PCPs in our study was one which actually only describes pure placebos. This definition, combined with the fact that most impure placebos were not regarded as placebos at all, means that most of the participating PCPs were not aware of the extent to which placebos are used in daily practice. The PCPs stated that they use placebos (both pure and impure) mainly in the case of non-severe diseases for which there was often no satisfactory somatic explanation. According to the PCPs, cases like this are often treated by complementary and alternative therapies and these, too, are associated with placebo effects. However, all PCPs felt that the ethical aspects of such treatment were unclear and they were unsure as to how to communicate the use of placebos to their patients. Most of them would appreciate ethical guidelines on how to deal with this issue.ConclusionsMany PCPs seem to be unaware that some of the drugs they prescribe are classified as impure placebos. Perceptions of effectiveness and doubts about the legal and ethical aspects of the use of placebos by PCPs may discourage their application. Dissemination of guidelines and consensus papers may be one approach, but it has to be acknowledged that the topic itself is in conflict with the PCPs' perception of themselves as professional and reliable physicians.