Meta-analysis of the effect of placebo on the outcome of medically treated reflux esophagitis

Placebo response in the prophylaxis of migraine: A meta-analysis

BACKGROUND

Migraine constitutes a good model for the study of placebo response. It is a well-defined disease, affects a large population and a great number of clinical trials have been performed, which have given homogeneous outcomes.

AIM

The aim of this meta-analysis is to evaluate the placebo response rate in migraine prophylaxis in all published clinical trials since 1988 and to estimate the influence of study design in response variability.

METHODS

A computer-based information search was conducted on the Medline database. The outcomes studied were patients who improved (reduction in migraine attacks of 50% or more); attacks per month, and patients with adverse events. Study design and countries in which the study was carried out were also analysed. The meta-analysis was computed using the Mantel-Haenszel test.

RESULTS

In the final analysis, 32 papers were considered. The pooled estimate of the placebo response (patients who improved) was 21%. The placebo response rates were significantly higher in studies with a parallel design than those in cross-over studies (p<0.01). This response was also higher in European studies than in those performed in North America (p<0.001). Adverse events occurred in 30% of the patients who took a placebo, and the percentage of patients with adverse events was significantly higher in the North American studies than in those conducted in Europe (p<0.01).

CONCLUSION

These data reinforce the need to consider the placebo effect when ascertaining the true therapeutic effect of any drug, as well as to design any clinical trial in the prophylaxis of migraine.

Meta-analysis: the effects of placebo treatment on gastro-oesophageal reflux disease

BACKGROUND

There appears to be a significant placebo response rate in clinical trials for gastro-oesophageal reflux disease. Little is known about the determinants and the circumstances associated with placebo response in the treatment of gastro-oesophageal reflux disease (GERD).

AIMS

To estimate the magnitude of the placebo response rate in randomized controlled trials for GERD and to identify factors that influence this response.

METHODS

A meta-analysis of randomized, double-blind, placebo-controlled trials, published in English language, which included >20 patients with GERD, treated with either a proton pump inhibitor or H(2)-receptor antagonist for at least 2 weeks. Medline, Cochrane and EMBASE databases were searched, considering only studies that reported a global response for 'heartburn'.

RESULTS

A total of 24 studies included 9989 patients with GERD. The pooled odds ratio (OR) for response to active treatment vs. placebo was 3.71 (95% CI: 2.78-4.96). The pooled estimate of the overall placebo response was 18.85% (range 2.94%-47.06%). Patients with erosive oesophagitis had a non-significantly lower placebo response rate than patients without it (11.87% and 18.31%, respectively; P = 0.246). Placebo response was significantly lower in studies of PPI therapy vs. studies of H(2) RAs (14.51% vs. 24.69%, respectively; P = 0.05).

CONCLUSIONS

The placebo response rate in randomized controlled trials for GERD is substantial. A lower placebo response was associated with the testing of PPIs, but not the presence of erosive oesophagitis.

Reflexology for the treatment of pain in people with multiple sclerosis: a double-blind randomised sham-controlled clinical trial

Multiple sclerosis (MS) results in pain and other symptoms which may be modified by conventional treatment, however, MS is still not curable. Several studies have reported positive effects of reflexology in the treatment of pain, however, no randomised controlled clinical trials for the treatment of pain have been conducted within this population. The objective of this study was to investigate the effectiveness of reflexology on pain in and MS population. We randomly allocated 73 participants to receive either precision or sham reflexology weekly for 10 weeks. Outcome measures were taken pre-and post-treatment with follow-up at 6 and 12 weeks by a researcher blinded to group allocation. The primary outcome measure recorded pain using a Visual Analogue Scale (VAS). A significant (p < 0.0001) and clinically important decrease in pain intensity was observed in both groups compared with baseline. Median VAS scores were reduced by 50% following treatment, and maintained for up to 12 weeks. Significant decreases were also observed for fatigue, depression, disability, spasm and quality of life. In conclusion, precision reflexology was not superior to sham, however, both treatments offer clinically significant improvements for MS symptoms via a possible placebo effect or stimulation of reflex points in the feet using non-specific massage.

The lessons learned from randomized clinical trials of GERD

Despite the huge number of randomized controlled clinical trials published on gastro-oesophageal reflux disease, the translation of the information gathered into clinical practice is rather limited. The aim of this article is to summarize the results of pivotal randomized controlled clinical trials and review articles on reflux disease and evaluate to what extent their results can be applied to current clinical practice. We reviewed the most relevant randomized controlled clinical trials and reviews since the publication of the first randomized controlled clinical trial on reflux oesophagitis (1978) to date. Six areas were explored, namely: (1) diagnostic "entry" criteria, (2) efficacy parameters, (3) duration of therapy, (4) degree of antisecretory effect, (5) placebo effect, (6) follow-up data. Gastro-oesophageal reflux disease is now the most frequent upper GI disorder treated by gastroenterologists in Europe and North America. There is still a dearth of information regarding the natural history of the disease. The types of information generated through randomized controlled clinical trials have had only limited applicability to routine clinical practice. In the future, large cooperative databases accumulating the clinical histories of a great variety of gastro-oesophageal reflux disease patients may help to provide us with the much needed insights into the natural history of this common disorder.

Reviving the old sermon of medicine with the placebo effect

OBJECTIVE: The message of the importance of a caring doctor-patient relationship is now like an old sermon which does not impact anyone's mind or action. Observing the healing practice of the old time physicians, who valued their attitudes and relationship with their patients more than the actual interventions, this paper reviews the literature on their main therapeutic device - the placebo effect - as a novel way of delivering this old sermon of medicine to contemporary doctors. DISCUSSION: There are countless historical and contemporary examples of the impressive placebo effect and although contested by some, it seems real and significant. The classic conditioning theory and the expectation theory explain reasonably well the mechanisms of the placebo effect, especially in conjunction with each other. The underlying biochemical pathway, according to the limited current knowledge, involves endorphins for pain and dopamine for Parkinson's disease. Finally, human factors such as the doctor's positive attitudes and a good doctor-patient relationship seem to be more essential than the placebo itself in eliciting the placebo effect. CONCLUSIONS: Given the body of evidence supporting the existence of significant placebo effect and the importance of the doctor-patient relationship in determining it, the human factors of the medical treatment should be emphasised in order to maximise the placebo effect and consequently the overall therapeutic effect of the healing acts.

The placebo response in the treatment of chronic fatigue syndrome: a systematic review and meta-analysis

OBJECTIVE

The placebo response is conventionally asserted to be high in chronic fatigue syndrome (CFS) because of the latter's subjective nature and obscure pathogenesis, but no systematic review of placebo responses has been undertaken. We report such a study. Patient expectation is known to be important in the placebo response. It is also known that CFS patients attending specialist clinics often have strong physical attributions regarding causation and hence skepticism about psychological or psychiatric interventions. If so, the placebo response in CFS may be influenced by the type of intervention according to its perceived rationale. We aimed to estimate the summary placebo response in clinical trials of CFS and to determine whether intervention type influences the placebo response in CFS.

METHODS

We searched Medline, Embase, Cochrane Library, PsychInfo, and the references of the identified articles, and contacted experts for controlled trials (randomized or nonrandomized) of any intervention on CFS patients reporting the placebo response as a clinical improvement in physical or general outcomes. Data were extracted from the articles and validity assessment conducted by one reviewer and checked by a second. Meta-analysis and metaregression were performed.

RESULTS

The pooled placebo response was 19.6% (95% confidence interval, 15.4-23.7), lower than predicted and lower than in some other medical conditions. The meta-regression revealed that intervention type significantly contributed to the heterogeneity of placebo response (p = .03).

CONCLUSION

In contrast with the conventional wisdom, the placebo response in CFS is low. Psychological-psychiatric interventions were shown to have a lower placebo response, perhaps linked to patient expectations.

Nonresorbable copolymer implantation for gastroesophageal reflux disease: a randomized sham-controlled multicenter trial

BACKGROUND & AIMS

This aim was to determine whether endoscopic implantation of a biocompatible nonresorbable copolymer (Enteryx; Boston Scientific Corp, Natick, MA) is a more effective therapy for gastroesophageal reflux disease (GERD) than a sham procedure.

METHODS

In a randomized, single-blind, prospective, multicenter clinical trial, 64 patients with GERD were enrolled whose symptoms were well controlled by proton pump inhibitor (PPI) therapy and rapidly recurred after cessation of PPI therapy. Thirty-two patients were assigned to Enteryx implantation and 32 to a sham procedure consisting of standard upper endoscopy. Patients in both groups with unsatisfactory symptom relief after 3 months were eligible for re-treatment by Enteryx implantation. The primary study end point was > or =50% reduction in PPI use. Secondary end points included > or =50% improvement in GERD score and the proportion of patients not undergoing re-treatment procedure. Follow-up evaluations were performed at 3 and 6 months.

RESULTS

The percentage of Enteryx-treated patients achieving a > or =50% reduction in PPI use (81%) was greater than that of the sham group (53%), with a rate ratio of 1.52 (confidence interval [CI], 1.06-2.28; P=.023). A higher proportion of the Enteryx (68%) than sham group (41%) ceased PPI use completely (rate ratio, 1.67; CI, 1.03-2.80; P=.033). GERD health-related quality of life heartburn score improvement > or =50% was achieved by 67% of the Enteryx group versus 22% of the sham group (rate ratio, 3.05; CI, 1.55-6.33; P <.001). More Enteryx-treated (81%) than sham-treated (19%) patients did not undergo re-treatment (rate ratio, 4.33; CI, 2.23-9.29; P <.001).

CONCLUSIONS

Enteryx implantation more effectively reduces PPI dependency and alleviates GERD symptoms than a sham procedure.

On-demand proton pump inhibitor therapy in patients with gastro-oesophageal reflux disease

On-demand therapy is an established modality in long-term therapy with histamine-2-receptor antagonists, in cases of mild non-erosive gastro-oesophageal reflux disease. In the literature, only a few studies have specifically addressed the problem of proton pump inhibitors on-demand treatment. The evidence, so far, available suggests that this might be an effective modality of long-term treatment in the majority of patients with non-erosive gastro-oesophageal reflux disease. This treatment modality appears to be the most cost-effective and the best tolerated medical regimen for gastro-oesophageal reflux disease. It also seems to be able to restore the impairment of health-related quality of life due to gastro-oesophageal reflux disease symptoms. Although the current standard of care for patients with non-erosive gastro-oesophageal reflux disease is maintenance therapy with daily administration of a proton pump inhibitor agent, on-demand therapy, with the same drug, may be a reasonable long-term choice. The ideal proton pump inhibitors for such treatment will be those with a more rapid onset of action, more profound acid inhibition, more predictable therapeutic effect and less drug-drug interactions. Newer proton pump inhibitors, like esomeprazole, the S-chiral isomer of omeprazole, are promising drugs for on-demand treatment of gastro-oesophageal reflux disease.

The clinical and economic impact of competing management strategies for gastro-oesophageal reflux disease

BACKGROUND

Gastro-oesophageal reflux disease (GERD) is a common disorder in the primary care setting. Traditional management strategies consist of sequentially intensive therapeutic trials followed by invasive diagnostic testing for nonresponders. A high dose proton pump inhibitor trial (the "proton pump inhibitor test") has been shown to be an accurate diagnostic alternative, and may be an efficient initial approach to patients with GERD symptoms.

AIM

To examine the clinical, economic and policy implications of alternative management strategies for GERD.

METHODS

Decision analysis was used to calculate the clinical and economic outcomes of competing management strategies. The traditional strategy incorporates sequential therapeutic trials with more intensive therapy ("step-up" approach) followed by sequential invasive diagnostic testing of nonresponders. The "proton pump inhibitor test" strategy includes an initial "proton pump inhibitor test" (7 days of omeprazole; 40 mg AM + 20 mg PM daily) followed by less intensive therapeutic trials in those testing positive ("step-down" approach) with sequential invasive diagnostic testing as needed. Cost estimates were based on Medicare reimbursement and average wholesale drug prices. Probability estimates were derived from a systematic review of the published medical literature. Model results are reported as the average and incremental cost-per-symptom free patient and cost-per-quality-adjusted life-years (QALYs) gained.

RESULTS

The average cost per patient was 1045 US dollars for the traditional step-up management strategy, compared to 1172 US dollars for the "proton pump inhibitor test" and step-down strategy. The percentage of patients who were symptom-free at 1 year was 50% for the traditional management strategy compared to 75% for the "proton pump inhibitor test" strategy. The "proton pump inhibitor test" strategy results in QALY gains of 0.01-0.05 depending on the utility estimate employed. The incremental cost-effectiveness ratio for the "proton pump inhibitor test" strategy is 510 US dollars per additional symptomatic cure over 1 year, and between 2822-10,160 US dollars per QALY gained. The traditional management strategy resulted in a greater than 5-fold increase in the utilization of upper endoscopy, which was partially offset by a 47% reduction in the use of ambulatory 24-h oesophageal pH monitoring. The reduced effectiveness of the traditional management strategy may be attributed in part to a 118% increase in the use of "high-dose" H2RAs while reducing the use of standard dose proton pump inhibitors by only 42% and "high-dose" proton pump inhibitors by 57%.

CONCLUSIONS

Based on the results of this analysis, strategies utilizing the initial PPI test followed by a "step-down" approach may result in improved symptom relief and quality of life over 1 year, and more appropriate utilization of invasive diagnostic testing at a small marginal increase in total costs. These findings warrant a prospective trial comparing these competing management strategies.

Ethics and clinical trials

The current reference guideline about ethics in clinical trials is the Declaration of Helsinki of human rights in medical research. Three major principles are emphasised: respect of the patient to accept or not to participate in a trial, the constraints and the presumed risks must be acceptable for patients included in a study, and vulnerable subjects should not participate in studies. The investigator is responsible for obtaining a free and well-informed consent from patients before their inclusion in a study. Where possible, a new drug should always first be compared to placebo in order to prove its superiority. Else, a small-sized trial comparing a new drug versus a reference treatment can lead to an erroneous conclusion of absence of difference. Moreover, good results or improvement are obtained in at least 30% of cases with placebo, whatever the disease. The use of placebo is unethical in life-threatening diseases and when an effective proved drug exists. The use of placebo is ethical in severe diseases with no efficient drug, in some severe diseases even when an active reference treatment is available, and in all moderate and functional diseases. In order to detect flawed studies, most journals now ask for any manuscript submitted and reporting results of a randomised clinical trial to join a checklist in order to verify the quality of the trial. Finally, it remains the responsibility of the doctor to decide whether or not a protocol is ethical, to participate or not and to include patients or not.

[Placebo effect in clinical trials]

BACKGROUND

It is well known that placebos evoke a variety of effects in the human body. It is less known that placebo medication can produce adverse drug reactions (ADRs).

METHOD

The efficacy and, as the main topic, the tolerability were investigated from an international clinical data pool on placebo-controlled randomized multicenter studies of 5 different groups of indications. The therapeutic areas analyzed were neuropsychiatry (nimodipine, ipsapirone), cardiology (nisoldipine), metabolism (acarbose) and gastroenterology (hydrotalcit).

RESULTS

The placebo efficacy was evident and varied not only in comparison to 5 indication groups analyzed, but also within them. Placebo showed for example hardly an effect on the symptomatology of stroke patients with a severe neurological deficit in comparison to verum while there was a 50% improvement in symptoms following placebo application in patients with a mild stroke. In angina patients exercise tolerance increased under placebo by 10% (time to onset of ST segment depression and symptoms of angina) while verum showed a 22% improvement. In diabetes placebo had no effect as compared to baseline and to a verum on blood glucose and HbA1C. ADRs could be observed under placebo treatment. The frequency and kind of placebo-induced ADRs varied also between the indication groups, i.e. typical CV side-effects were observed in CV controls. The placebo ADR profile was similar to the reference drug also. Some ADRs were reported even more frequently under placebo than under verum, like "dry mouth" in patients with general anxiety status.

CONCLUSIONS

Placebo therapy is frequently effective and is not a "non-therapy". Placebo effects can be shown only by direct comparison with a "non-therapy". A placebo therapy is frequently accompanied by adverse drug reactions (ADRs) just as a verum therapy. Placebo ADRs are frequently illness- and verum-specific. Effects and ADRs of placebo therapy must be known, to judge the effect of verum medication in controlled clinical trials. The mechanisms of placebo effects are manifold (e.g. endorphine release, conditioned learning). Since placebo therapy outside of evidence-based medicine (use of drugs without proven efficacy = pseudoplacebos) may potentially also cause serious side effects, the use may not only be useless but also harmful.

Does quality of reports of randomised trials affect estimates of intervention efficacy reported in meta-analyses?

BACKGROUND

Few meta-analyses of randomised trials assess the quality of the studies included. Yet there is increasing evidence that trial quality can affect estimates of intervention efficacy. We investigated whether different methods of quality assessment provide different estimates of intervention efficacy evaluated in randomised controlled trials (RCTs).

METHODS

We randomly selected 11 meta-analyses that involved 127 RCTs on the efficacy of interventions used for circulatory and digestive diseases, mental health, and pregnancy and childbirth. We replicated all the meta-analyses using published data from the primary studies. The quality of reporting of all 127 clinical trials was assessed by means of component and scale approaches. To explore the effects of quality on the quantitative results, we examined the effects of different methods of incorporating quality scores (sensitivity analysis and quality weights) on the results of the meta-analyses.

FINDINGS

The quality of trials was low. Masked assessments provided significantly higher scores than unmasked assessments (mean 2.74 [SD 1.10] vs 2.55 [1.20]). Low-quality trials (score < or = 2), compared with high-quality trials (score > 2), were associated with an increased estimate of benefit of 34% (ratio of odds ratios [ROR] 0.66 [95% CI 0.52-0.83]). Trials that used inadequate allocation concealment, compared with those that used adequate methods, were also associated with an increased estimate of benefit (37%; ROR=0.63 [0.45-0.88]). The average treatment benefit was 39% (odds ratio [OR] 0.61 [0.57-0.65]) for all trials, 52% (OR 0.48 [0.43-0.54]) for low-quality trials, and 29% (OR 0.71 [0.65-0.77]) for high-quality trials. Use of all the trial scores as quality weights reduced the effects to 35% (OR 0.65 [0.59-0.71]) and resulted in the least statistical heterogeneity.

INTERPRETATION

Studies of low methodological quality in which the estimate of quality is incorporated into the meta-analyses can alter the interpretation of the benefit of intervention, whether a scale or component approach is used in the assessment of trial quality.