placebo
Acupuncture is often recommended as a treatment for shoulder pain, but its effectiveness is far from proven. A new study has just been published; but does it change this uncertainty?
A total of 227 patients with subacromial pain syndrome were recruited to this RCT. The patients were allocated to three groups who received either A) group exercise, B) group exercise plus acupuncture or C) group exercise plus electro-acupuncture. The primary outcome measure was the Oxford Shoulder Score. Follow-up was post treatment, and at 6 and 12 months. Data were analysed on intention-to-treat principles with imputation of missing values.
Treatment groups were similar at baseline. All treatment groups demonstrated improvements over time. Between-group estimates were, however, small and non-significant.
The authors concluded that neither acupuncture nor electro-acupuncture were found to be more beneficial than exercise alone in the treatment of subacromial pain syndrome.
Well, that was to be expected!… I hear the rationalists amongst us exclaim.
Actually, I am not so sure.
One could easily have expected that the acupuncture groups (B and C) show a significant advantage over group A.
Why?
Because acupuncture is a ‘theatrical placebo’, a ritual that impresses patients and thus impacts on results, particularly on subjective outcomes like pain. If the results had shown a benefit for acupuncture + exercise (groups B and C) versus exercise alone (group A), what would we have made of it? Acupuncture fans would surely have claimed that it is evidence confirming acupuncture’s effectiveness. Sceptics, on the other hand, would have rightly insisted that it demonstrates nothing of the sort – it merely confirms that placebo effects can affect clinical outcomes such as pain.
As it turned out, however, this trial results happened to indicate that these placebo-effects can be so small that they fail to reach the level of statistical significance.
I think there is one noteworthy message here: RCTs with such a design (no adequate control for placebo effects) can easily generate false-positive results (in this case, this did not happen, but it was nevertheless a possible outcome). Such studies are popular but utterly useless: they don’t advance our knowledge one single iota. If that is so, we should not waste our resources on them because, in the final analysis, this is not ethical. In other words, we must stop funding research that has little or no chance of advancing our knowledge.
This new RCT was embargoed until today; so, I had to wait until I was able to publish my comments. Here are the essentials of the study:
The Swedish investigators compared the effect of two types of acupuncture versus no acupuncture in infants with colic in public child health centres (CHCs). The study was designed as a multicentre, randomised controlled, single-blind, three-armed trial (ACU-COL) comparing two styles of acupuncture with no acupuncture, as an adjunct to standard care. Among 426 infants whose parents sought help for colic and registered their child’s fussing/crying in a diary, 157 fulfilled the criteria for colic and 147 started the intervention.
Parallel to usual care, study participants visited the study CHC twice a week for 2 weeks. Thus, all infants received usual care plus 4 extra visits to a CHC, during which parents met a nurse for 20–30 min and were able to discuss their infant’s symptoms. Together these were considered to represent gold standard care. The nurse listened, and gave evidence-based advice and calming reassurance. Breastfeeding mothers were encouraged to continue breastfeeding. At each visit, the study nurse carried the infant to a separate treatment room where they were left alone with the acupuncturist for 5 min.
The acupuncturist treated the baby according to group allocation and recorded the treatment procedures and any adverse events. Disposable stainless steel 0.20×13 mm Vinco needles (Helio, Jiangsu Province, China) were used. Infants allocated to group A received standardised MA at LI4. One needle was inserted to a depth of approximately 3 mm unilaterally for 2–5 s and then withdrawn without stimulation. Infants allocated to group B received semi-standardised individualised acupuncture, mimicking clinical TCM practice. Following a manual, the acupuncturists were able to choose one point, or any combination of Sifeng, LI4 and ST36, depending on the infant’s symptoms, as reported in the diary. A maximum of five insertions were allowed per treatment. Needling at Sifeng consisted of 4 insertions, each to a depth of approximately 1 mm for 1 s. At LI4 and ST36, needles were inserted to a depth of approximately 3 mm, uni- or bilaterally. Needles could be retained for 30 seconds. De qi was not sought, therefore stimulation was similarly minimal in groups A and B. Infants in group C spent 5 min alone with the acupuncturist without receiving acupuncture.
The effect of the two types of acupuncture was similar and both were superior to gold standard care alone. Relative to baseline, there was a greater relative reduction in time spent crying and colicky crying by the second intervention week (p=0.050) and follow-up period (p=0.031), respectively, in infants receiving either type of acupuncture. More infants receiving acupuncture cried <3 hours/day, and thereby no longer fulfilled criteria for colic, in the first (p=0.040) and second (p=0.006) intervention weeks. No serious adverse events were reported.
The authors concluded that acupuncture appears to reduce crying in infants with colic safely.
Notice that the investigators are cautious and state in the abstract that “acupuncture appears to reduce crying…” Their conclusions from the actual article are, however, quite different; here they state the following:
Among those initially experiencing excessive infant crying, the majority of parents reported normal values once the infant’s crying had been evaluated in a diary and a diet free of cow’s milk had been introduced. Therefore, objective measurement of crying and exclusion of cow’s milk protein are recommended as first steps, to avoid unnecessary treatment. For those infants that continue to cry >3 hours/day, acupuncture may be an effective treatment option. The two styles of MA tested in ACU-COL had similar effects; both reduced crying in infants with colic and had no serious side effects. However, there is a need for further research to find the optimal needling locations, stimulation and treatment intervals.
Such phraseology is much more assertive and seems to assume acupuncture caused specific therapeutic effects. Yet, I think, this assumption is not warranted.
In fact, I believe, the study shows almost the opposite of what the authors conclude. Both minimal and TCM acupuncture seemed to reduce the symptoms of colic compared to no acupuncture at all. I think, this confirms previous research showing that acupuncture is a ‘theatrical placebo’. The study was designed without an adequate placebo group. It would have been easy to use some form of sham acupuncture in the control group. Why did the authors not do that? Heaven knows, but one might speculate that they were aiming for a positive result – and what better way to ensure it than with a ‘no treatment’ control group?
There are, of course, numerous other flaws. For instance, Prof David Colquhoun FRS, Professor of Pharmacology at University College London, criticised the study because of its lousy statistics:
START OF QUOTE
“It is truly astonishing that, in the 21st century, the BMJ still publishes a journal devoted to a form of pre-scientific medicine which after more than 3000 trials has still not been able to produce convincing evidence of efficacy1. Like most forms of alternative medicine, acupuncture has been advocated for a vast range of problems, and there is little evidence that it works for any of them. Colic has not been prominent in these claims. What parent would think that sticking needles into their baby would stop it crying? The idea sounds bizarre. It is. This paper certainly doesn’t show that it works.
“The statistical analysis in the paper is incompetent. This should have been detected by the referees, but wasn’t. For a start, the opening statement, ‘A two-sided P value ≤0.05 was considered statistically significant’ is simply unacceptable in the light of all recent work about reproducibility. Still worse, Table 1 uses the description ‘statistical tendency towards significance (p=0.051–0.1)’.
“Worst of all, Table 1 reports 24 different P values, of which three are (just) below 0.05. Yet no correction has been used for multiple comparisons. This is very bad practice. It’s highly unlikely that, if the proper correction had been done, any of the results would have given a type 1 error rate below 5%.
“Even were it not for this, most of the ‘significant’ P values are marginal (only slightly less than 0.05). It is now well known that the type 1 error rate gives an optimistic view. What matters is the false positive rate – the chance that a ‘significant’ result is a false positive. A p-value close to 0.05 implies that there is at least a 30% chance that they are false positives. If one thought, a priori, that the chance of colic being cured by sticking needles into a baby was less than 50%, the false positive rate could easily be greater than 80%2. It is now recognised that this misinterpretation of p-values is a major contributor to the crisis of reproducibility.
“Other problems concern the power calculation. A priori calculations of power are well-known to be overoptimistic, because small trials usually overestimate the effect size. In this case the initial estimated sample size was not attained, and a rather mysterious recalculation of power was used.
“Another small problem: the discussion points out that ‘the majority of infants in this cohort did not have colic’.
“The nature of the control group is not very clear. An appropriate control might have been to cuddle the baby – this was used in a study in which another implausible treatment, chiropractic, was shown not to work. This appears not to have been done.
“Lastly, p-values are reported in the text without mention of effect sizes. This is contrary to all statistical advice.
“In conclusion, the design of the trial is reasonable (apart from the control group) but the statistical analysis is appalling. It’s very likely that there aren’t any real effects of acupuncture at all. This paper serves more to muddy the waters than to add useful information. It’s a model for the sort of mistakes that have led to the crisis in reproducibility. The BMJ should not be publishing this sort of stuff, and the referees seem to have no understanding of statistics.”
END OF QUOTE
Despite these rather obvious – some would say fatal – flaws, the editor of ACUPUNCTURE IN MEDICINE (AIM) thought this trial to be so impressively rigorous that he issued a press-release about it. This, I think, is particularly telling, perhaps even humorous: it shows what kind of a journal AIM is, and also provides an insight into the state of acupuncture research in general.
The long and short of it is that conclusions about specific therapeutic effects of acupuncture are not permissible. We know that colicky babies respond even to minimal attention, and this trial confirms that even a little additional TLC in the form of acupuncture will generate an effect. The observed outcome is most likely unrelated to acupuncture.
If you want to scientifically investigate this question, it might be a good idea NOT to start with the following sentence: “Auricular acupuncture (AA) is effective in the treatment of preoperative anxiety”. Yet, this is exactly what the authors did in their recent publication.
The aim of this new study was to investigate whether AA can reduce exam anxiety as compared to placebo and no intervention. Forty-four medical students were randomized to receive AA, placebo, or no intervention in a crossover manner. Subsequently they completed three comparable oral anatomy exams with an interval of one month between the exams/interventions.
A licensed acupuncturist with more than five years of experience with this technique applied AA at the acupuncture points MA-IC1 (Lung), MA-TF1 (ear Shenmen), MA-SC (Kidney), MA-AT1 (Subcortex) and MA-TG (Adrenal gland) bilaterally. Indwelling fixed ‘New Pyonex’ needles embedded in a skin-coloured adhesive tape were used for AA. The participants were instructed by the acupuncturist to stimulate the auricular needles for 3–5 minutes, if they felt anxious. For the placebo procedure, ‘New Pyonex’ placebo needles were attached to five sites on the helix of the auricle bilaterally. ‘New Pyonex’ placebo needles have the same appearance as AA needles but consist of self-adhesive tape only. In order to avoid potential physiologic effects of acupressure, the participants were not instructed to stimulate the attached ‘New Pyonex’ placebo needles. AA and placebo needles were left in situ until the next day and were removed out of sight of the participants after the exam by the investigator, who was not involved in acupuncture procedure
Levels of anxiety were measured using a visual analogue scale before and after each intervention as well as before each exam. Additional measures included the State-Trait-Anxiety Inventory, duration of sleep at night, blood pressure, heart rate and the extent of participant blinding.
All included participants finished the study. Anxiety levels were reduced after AA and placebo intervention compared to baseline and the no intervention condition (p < 0.003). Moreover, AA was also better at reducing anxiety than placebo in the evening before the exam (p = 0.018). Participants were able to distinguish between AA and placebo intervention.
The authors concluded that both auricular acupuncture and placebo procedure were shown to be effective in reducing levels of exam anxiety in medical students. The superiority of verum AA over placebo AA and no intervention is considered to be due to stimulation of cranial nerves, but may have been increased in effect by insufficient participant blinding.
Here are just three of the major concerns I have about this study:
- The trial design seems odd: a crossover study can only work well, if there is a stable baseline. This may not be the case with three consecutive exams; the anxiety experienced by students is bound to get less as time goes by. I think anyone who has passed a series of exams will confirm that there is a large degree of habituation.
- It seems inadequate to employ just one acupuncturist; it means that the trial might end up testing not acupuncture per se but the skills of the therapist.
- The placebo used for this study cannot possibly have fooled anyone into believing that it was real AA; volunteers were not even instructed to ‘stimulate’ the placebo devices. The difference to the ‘real thing’ must have been very clear to all involved. This means that the control for placebo-effects was woefully incomplete. In turn, this means that the observed outcomes are most likely due to residual bias.
In view of these concerns, allow me to re-phrase the authors’ conclusions:
THE RESULTS OF THIS POORLY-DESIGNED STUDY ARE DIFFICULT TO INTERPRET. MOST LIKELY THEY SHOW THAT ACUPUNCTURE IS NOT EFFECTIVE BUT MERELY WORKS THROUGH A PLACEBO-RESPONSE.
You probably remember: the US Federal Trade Commission’s (FTC) has issued a statement announcing that unsupported claims for homeopathic remedies will be no longer allowed. Specifically, they said that, in future, homeopathic remedies have to be held to the same standard as other medicinal products. In other words, American companies must now have reliable scientific evidence for health-related claims that their products can treat specific conditions and illnesses.
Now the AMERICAN INSTITUTE OF HOMEOPATHY (AIH) has published a rebuttal. It is hilarious and embarrassing in equal measure. Here it is in full (I have only omitted their references – they can be seen in the linked original – and added footnotes in bold square brackets with my very short comments):
START OF QUOTE
November 30, 2016
The American Institute of Homeopathy applauds the Federal Trade Commission’s (FTC) goal of protecting the American public from false advertising claims, but in a recent circumstance we believe the FTC has overstepped its jurisdictional bounds and promulgated false information in what appears to be a bid to restrict health care choices [1] available to the American public.
In Response to the recent Enforcement Policy Statement1 and a Consumer Information Blog,2 both issued by the FTC on November 15, 2016, the American Institute of Homeopathy registers our strong concern regarding the content of the following inaccurate statements:
- “Homeopathy… is based on the view that disease symptoms can be treated by minute doses of substances that produce similar symptoms…”
Homeopathy is not based on a “view” or an opinion. It is based on reliable, reproducible, clinically acquired, empiric evidence [2] gathered through two centuries of corroborated data, assisted by thousands of practitioners worldwide [3], demonstrating the actions of different medicinal substances in living systems, aka: the science of homeopathy. In fact, the homeopathic scientific community were pioneers of the modern scientific method including the widespread adoption of blinded and placebo controlled studies in 1885 [4], decades before conventional medicine.3
Homeopathy is not based on a theory or on conjecture, but on principles that have been confirmed by long-studied clinical data, meticulously gathered and analyzed over many years [5].
- “Many homeopathic products are diluted to such an extent that they no longer contain detectable levels of the initial substance.”
While the dilution and succussion process of formulating homeopathic medicines does reduce the concentration (and the toxicity) of the original substances, detectable amounts of these materials remain quantifiable in the form of nanoparticles [6] dispersed throughout.4 Multiple independent laboratories, worldwide have confirmed that these nanoparticles persist,5 and that they are biologically active.6 Many other homeopathic products (particularly those sold OTC and described as “low potency”) have dilute amounts of the original substance [7] that remain chemically detectable by straightforward titration.
- “…homeopathic product claims are not based on modern scientific methods…”
This statement is false and misleading. The active ingredients within most OTC homeopathic products have hundreds or thousands of case reports from physicians who have used these medicines [8]. These reports of direct clinical experiences establish a collective, real-world dataset that demonstrates which conditions have been observed to respond to treatment. Such historical data is similar to the types of information used to demonstrate effectiveness for many conventional OTC medicines on the market today [9].
The Homeopathic Pharmacopeia Convention of the United States (HPCUS) maintains a formulary describing the appropriate manufacturing standards for homeopathic medicines [10]. Every homeopathic manufacturer member of the American Association of Homeopathic Pharmacists in good ethical standing complies with both manufacturing and labeling standards set by the HPCUS. Consumers should be cautious when using any products that are not distinguished by conformance with “HPUS” on the label.
- “…the case for efficacy is based solely on traditional homeopathic theories…”
This statement is false. Neither homeopathy nor homeopathic efficacy is based on any theories. Efficacy for various homeopathic medicines has been established by scientifically reproducible clinical empiric research evidence [11] and cured patient cases followed over many years [12]. Homeopathy is an evidence-based medical subspecialty rooted in patient care.
- “…there are no valid studies using current scientific methods showing the product’s efficacy.”
While this statement may have limited accuracy with respect to some OTC products, it is false and misleading with respect to most homeopathic medicines listed in the Homeopathic Pharmacopeia of the United States. Hundreds of state-of-the-art double-blinded, randomized, placebo-controlled studies, many in peer-reviewed journals, demonstrate the superior efficacy of homeopathic medicines in a wide range of conditions, including asthma,7 depression and anxiety,8 chronic illness,9 allergic rhinitis,10 hypertension,11 headaches/migraines,12 sepsis,13 mild traumatic brain injury,14 otitis media,15 cancer,16 and many other conditions [13]. The American Institute of Homeopathy maintains and continually updates an extensive database, available free to the public, with over 6,000 research articles [14].17
Multiple meta-analyses published in peer reviewed medical journals that conclude that homeopathic medicine effects are superior to placebo [15] and that additional study of this therapeutic system is warranted.18,19,20,21,22,23 To that end, we encourage the National Institutes of Health to reverse their current position of blocking funding for homeopathic trials.24
- “…marketing claims that such homeopathic products have a therapeutic effect lack a reasonable basis and are likely misleading…”
The conclusion of whether a product has a “reasonable basis” is entirely irrelevant if that product has demonstrable clinical effectiveness. The important question, when it comes to homeopathy, is whether it is effective in clinical settings, not whether it has a “reasonable basis” for how it works. The mechanism by which homeopathy works differs from conventional medicines [16], but this fact does not make these products “misleading”.
Several recent class-action lawsuits brought against homeopathic manufacturers confirm that marketing practices were neither deceptive nor misleading [17].25
The FTC’s inability to formulate a reasonable basis for why homeopathic medicines work should not enter into any governmental enforcement policy statement. The FTC is not a medical organization, lacks expertise in interpreting scientific research [18], and is not qualified to make any comment on the validity of any field of medicine. To be less misleading, the FTC should exclude opinions from its policy statements.
- “Homeopathy: Not backed by modern science”
Homeopathy, as a system of medicine, does not fall under the purview of the FTC. Therefore, the FTC has been reckless in expressing an opinion of this magnitude. In this situation, the FTC’s comments can only be construed as being prejudicially biased and intentionally discriminatory against homeopathy. Such statements cause unwarranted harm to public trust and damage to a respected traditional system of medicine in the United States [19].
The American Institute of Homeopathy strongly objects to the FTC’s characterization of the entire field of homeopathic medicine as being without scientific evidence of efficacy. These comments are unqualified and wholly lacking in merit. The release of this Enforcement Policy Statement serves only to align the FTC with several recently released scientifically fraudulent [20] reports by a variety of pseudoscientists [21] and lowers the credibility of this valued consumer protection agency.
This type of misinformation should be embarrassing to a government organization striving to be nonpartisan and objective. The FTC owes an apology to the American Institute of Homeopathy as well as the many consumer groups that look toward this agency for fair and accurate information.
END OF QUOTE
My comments:
1 In healthcare, choice must be restricted to treatments which demonstrably generate more good than harm.
2 The AIH seems to be unaware of the difference between the nature of evidence, anecdote and experience.
3 Fallacy – appeal to popularity.
4 The first randomized, placebo-controlled study of homeopathy was, in fact, published in 1835 – its results were negative.
5 Fallacy – appeal to tradition.
6 The nano-particle explanation of homeopathy is but a theory (at best).
7 Fallacy – appeal to tradition.
8 Fallacy – appeal to authority.
9 Really? Which ones? Examples would help, but I doubt they exist.
10 The proper manufacturing of nonsense must still result in nonsense.
11 See footnote number 2
12 Fallacy – appeal to tradition.
13 For all of these conditions, the totality of the reliable evidence fails to demonstrate efficacy.
14 In this context, only clinical trials are relevant, and their number is nowhere near 6,000.
15 Most of the independent systematic reviews fail to be positive.
16 The mechanism is well-known and is called ‘placebo-effect’.
17 Many class actions also went against the manufacturers of homeopathic preparations.
18 I assume they ‘bought in’ the necessary expertise.
19 Surely, the damage is only to the cash-flow of firms selling bogus products.
20 Really? Name the report you libel here or be quiet!
21 Name the individuals you attack in this way or be quiet!
I must say, I had fun reading this. In fact, I cannot remember having seen a document by an organisation of healthcare professionals which was so embarrassingly nonsensical that it becomes comedy gold. If one of my PhD students, for instance, had submitted such drivel, I would have had no choice but to fail him or her.
Having said that, I need to stress to the AIH:
FULL MARKS FOR AMUSEMENT!!!
The placebo response might be important in clinical practice, but it is certainly difficult to study and the findings of such investigations can be confusing. This seems to be exemplified by two new trials.
The first study examined the possibility of using theatrical performance tools, including stage directions and scripting, to reproducibly manipulate the style and content of a simulated doctor-patient encounter and influence the placebo response (defined as improvement of clinical outcome in individuals receiving inactive treatment) in experimental pain.
A total of 122 healthy volunteers were exposed to experimental pain using the cold pressor test and assessed for pain threshold and tolerance before and after receiving a placebo cream from a “doctor” impersonated by a trained actor. The actor alternated between two distinct scripts and stage directions. One script emulated a standard doctor-patient encounter (scenario A), while the other emphasized elements present in ritual healing such as attentiveness and strong suggestion (scenario B).
The placebo response size was calculated as the % difference in pain threshold and tolerance after exposure relative to baseline. Subjects demonstrating a ≥30% increase in pain threshold or tolerance relative to baseline were defined as responders. Each encounter was videotaped in its entirety.
Inspection of the videotapes confirmed the reproducibility and consistency of the distinct scenarios enacted by the “doctor”-performer. Furthermore, scenario B resulted in a significant increase in pain threshold relative to scenario A. This increase derived from the placebo responder subgroup; as shown by two-way analysis of variance (performance style, F = 4.30; p = 0.040; η(2) = 0.035; style × responder status interaction term, F = 5.21; p = 0.024) followed by post hoc analysis showing a ∼60% increase in pain threshold in responders exposed to scenario B (p = 0.020).
Performance style and response size in placebo responders and non-responders. Bars represent mean ± SE of % change in CPT threshold of 60 subjects in scenario A: 53 non-responders vs. 7 responders and 62 subjects in scenario B: 51 non-responders and 11 responders. Two-way ANOVA by performance style and responsiveness revealed significant effects of doctor’s performance (F = 4.30; p = 0.040; η2 = 0.035) and responsiveness (F = 134.71; p < 0.001) as well as a significant interaction term (F = 5.21; p = 0.024). ∗p = 0.020, Fisher’s least significant difference post hoc test.
The authors concluded that these results support the hypothesis that structured manipulation of physician’s verbal and non-verbal performance, designed to build rapport and increase faith in treatment, is feasible and may have a significant beneficial effect on the size of the response to placebo analgesia. They also demonstrate that subjects, who are not susceptible to placebo, are also not susceptible to performance style.
In the second study, the authors investigated if an implicit priming procedure, where participants were unaware of the intended priming influence, affected placebo analgesia.
In a double-blind experiment, healthy participants (n = 36) were randomized to different implicit priming types; one aimed at increasing positive expectations and one neutral control condition. First, pain calibration (thermal) and a credibility demonstration of the placebo analgesic device were performed. In a second step, an independent experimenter administered the priming task; Scrambled Sentence Test. Then, pain sensitivity was assessed while telling participants that the analgesic device was either turned on (placebo) or turned off (baseline). Pain responses were recorded on a 0-100 Numeric Response Scale.
Overall, there was a significant placebo effect (p < 0.001), however, the priming conditions (positive/neutral) did not lead to differences in placebo outcome. Prior experience of pain relief (during initial pain testing) correlated significantly with placebo analgesia (p < 0.001) and explained 34% of placebo variance. Trait neuroticism correlated positively with placebo analgesia (p < 0.05) and explained 21% of placebo variance.
The authors concluded that priming is one of many ways to influence behaviour, and non-conscious activation of positive expectations could theoretically affect placebo analgesia. Yet, we found no SST priming effect on placebo analgesia. Instead, our data point to the significance of prior experience of pain relief, trait neuroticism and social interaction with the treating clinician.
The two studies are similar but generate somewhat contradictory results. In the discussion section, the authors of the first paper stress that “replication of our findings in clinical populations; employing professional physicians of both sexes, are necessary in order to establish their generality and possible application in medical training, with the aim of improving patient outcome across diseases and treatment modalities.” This is certainly true. They continue by stating that “future studies using performance tools in clinical trial settings could demonstrate the potential of borrowing performance principles and techniques from traditional healing and applying them to physician–patient encounters in Western medicine, following certain necessary modifications. Performance tools could thus eventually be incorporated into the systematic training of physicians and medical students, possibly to complement programs in Narrative Medicine and Relational Medicine.”
These ideas are not dissimilar to what we have been discussing on this blog repeatedly. For instance, I have previously tried to explain that “the science and the art of medicine are essential elements of good medicine. In other words, if one is missing, medicine is by definition not optimal. In vast areas of alternative medicine, the science-element is woefully neglected or even totally absent. It follows, that these areas cannot be good medicine. In some areas of conventional medicine, the art-element is weak or neglected. It follows that, in these areas, medicine is not good either.”
The fact that the two studies above show contradictory findings is not easy to interpret. Possibly, this shows how fragile the placebo response can be. It can be influenced by a multitude of factors related to an experiment or the clinical setting. If that is so, and placebo effects are truly unreliable, it would be yet another argument for not relying on them in clinical routine. In my view, clinicians should try to maximize them where they can. Yet placebo effects are not normally a justification for employing placebo therapies in clinical practice. In other words, the fact that a bogus treatment can generate a placebo response is not a good reason for using it on patients who need help.
Good clinicians have probably always been good ‘performers’. Alternative practitioners tend to be excellent ‘performers’, and I am sure their success is mainly due to this ability. I see little reason why conventional practitioners should not (re-)learn the skills that once upon a time were called ‘good bed-side manners’. Maximizing the placebo effect in this way might maximize the benefit patients experience – and for that we do not require the placebo-therapies of alternative medicine.
A new study tested the efficacy of chiropractic spinal manipulative therapy (CSMT) for migraine. It was designed as a three-armed, single-blinded, placebo -controlled RCT of 17 months duration including 104 migraineurs with at least one migraine attack per month. Active treatment consisted of CSMT (group 1) and the placebo was a sham push manoeuvre of the lateral edge of the scapula and/or the gluteal region (group 2). The control group continued their usual pharmacological management (group 3).
The RCT began with a one-month run-in followed by three months intervention. The outcome measures were quantified at the end of the intervention and at 3, 6 and 12 months of follow-up. The primary end-point was the number of migraine days per month. Secondary end-points were migraine duration, migraine intensity and headache index, and medicine consumption.
The results show that migraine days were significantly reduced within all three groups from baseline to post-treatment (P < 0.001). The effect continued in the CSMT and placebo groups at all follow-up time points (groups 1 and 2), whereas the control group (group 3) returned to baseline. The reduction in migraine days was not significantly different between the groups. Migraine duration and headache index were reduced significantly more in the CSMT than in group 3 towards the end of follow-up. Adverse events were few, mild and transient. Blinding was strongly sustained throughout the RCT.
The authors concluded that it is possible to conduct a manual-therapy RCT with concealed placebo. The effect of CSMT observed in our study is probably due to a placebo response.
Chiropractors often cite clinical trials which suggest that CSMT might be effective. The effects sizes are rarely impressive, and it is tempting to suspect that the outcomes are mostly due to bias. Chiropractors, of course, deny such an explanation. Yet, to me, it seems fairly obvious: trials of CSMT are not blind, and therefore the expectation of the patient is likely to have major influence on the outcome.
Because of this phenomenon (and several others, of course), sceptics are usually unconvinced of the value of chiropractic. Chiropractors often respond by claiming that blind studies of physical intervention such as CSMT are not possible. This, however, is clearly not true; there have been several trials that employed sham treatments which adequately mimic CSMT. As these frequently fail to show what chiropractors had hoped, the methodology is intensely disliked by chiropractors.
The above study is yet another trial that adequately controls for patients’ expectation, and it shows that the apparent efficacy of CSMT disappears when this source of bias is properly accounted for. To me, such findings make a lot of sense, and I suspect that most, if not all the ‘positive’ studies of CSMT would turn out to be false positive, once such residual bias is eliminated.
Over on ‘SPECTATOR HEALTH’, we have an interesting discussion (again) about homeopathy. The comments so far were not short of personal attacks but this one by someone who called himself (courageously) ‘Larry M’ took the biscuit. It is so characteristic of deluded homeopathy apologists that I simply have to share it with you:
Ernst grew up with homeopathy [1], saw how well it worked [2], and chose to become a so-called expert in alternative medicine [3]. To his surprise, he met with professional disapproval [4]. Being the weak ego-driven person that he is [5], he saw an opportunity to still come out on top. He sold his soul in exchange for the notoriety that he now receives for being the crotchety old homeopathy hater that he has become [6]. As with all homeopathy haters, his fundamentalist zeal [7] is evidence of his secret self-loathing [8] and fear that his true beliefs will be found out [9]. It’s no different than the evangelical preacher who rails against gays only to be eventually found out to be a closeted gay [10].
There is not much that makes me speechless these days, but this comment almost did. There is someone who clearly does not even know me and he takes it upon himself to interpret and re-invent my past, my motives and my actions at will. How deluded is that?
After re-reading the comment, I began to see the funny side of it, had a giggle and decided to add a few elements of truth in the form of this blog-post. So I took the liberty to insert some reference numbers into Larry’s text which refer to my brief points below.
- This is at least partly true; our family doctor was a prominent homeopath. Whenever one of us was truly ill, he employed conventional treatments.
- I was impressed as a young physician working in a homeopathic hospital to see that patients improved on homeopathy – even though, at medical school, I had been told that the remedies were pure placebos. This contradiction fascinated me, and I began to do some own research into the subject.
- I did not ‘choose’, I had a genuine interest; and I don’t think that I am a ‘so called’ expert – after 2 decades of research and hundreds of papers, this attribute seems a trifle unfitting.
- The disapproval came from the homeopathy fans who were irritated that someone had the audacity to undertake a truly CRITICAL assessment of their treatments and actions.
- The amateur psychology here speaks for itself, I think.
- Yes, I am no spring chicken! But I am not a ‘hater’ of anything – I try to create progress by convincing people that it is prudent to go for treatments that are evidence-based and avoid those that do not generate more good than harm.
- This attitude is not a ‘fundamental zeal’, it is the only responsible way forward.
- This made me laugh out loud! Nothing could be further from the truth.
- My ‘true belief’ is that patients deserve the best treatments available. I have no fear of being ‘found out’; on the contrary, during my career I stood up to several challenges of influential people who tried to trip me up.
- This is hilarious – does Larry not feel how pompously ridiculous and ridiculously pompous he truly is?
This might be all too trivial, if such personal attacks were not an almost daily event. The best I can do with them, I have concluded, is to expose them for what they are and demonstrate how dangerously deluded the advocates of quackery really are. In this way, I can perhaps minimize the harm these people do to public health and medical progress.
The ‘Deutsche Apotheker Zeitung’, a paper for German pharmacists, rarely is the most humorous of publications. However, recently they reported on a battle between the EU and the European producers of homeopathic remedies – a battle over mercury which has, I think, hints of Monty Python and the Flying Circus.
The EU already has strict regulations on the use of mercury, for obvious reasons, they apply particularly to medicines. The law in this area is now 8 years old and is about to be replaced by a new one which is even stricter. A draft has been recently published here.
The new law would prohibit all mercury in medicinal products, except for some used in dentistry. For the homeopathic and anthroposophic manufacturers, this is not good news because they have many remedies on the market that have the word ‘mercury’ on the label. Consequently, they fear that the sale of these products might be impeded or even become impossible in the EU.
„Quecksilber und Quecksilberverbindungen stellen für manche homöopathische und andere traditionelle Arzneimittel einen unverzichtbaren Bestandteil dar“ (Mercury and mercury compounds are an essential ingredient of some homeopathic and other traditional medicines) .. “Es steht keine Quecksilber-freie Alternative zur Verfügung, die als aktiver Bestandteil in der Therapie mit homöopathischen oder anderen traditionellen Arzneimitteln verwendet werden könnte“ (There is no mercury-free alternative that could be used in these medications”) wrote the Dachverband der Arzneimittelhersteller im Bereich der Selbstmedikation (AESGP) (a lobby group of the homeopathic manufacturers) in a comment adding that „Diese Produkte sind seit Dekaden auf dem europäischen Markt und gehören zum Arzneimittel-Werkzeugkoffer” (these products are on the market since decades and belong to the medical tool-kit)… and that these products contain merely tiny amounts of mercury – even the largest manufacturers of these remedies only require a few milligrams for their production.
The plea of the manufacturers therefore is for an exemption from the new law which would allow the trade of mercury-containing remedies in future. They even have the support of some health politicians; for instance Peter Liese CDU favours an exemption for homeopathic medicines. The next meeting of the EU committee on public health will vote on the matter.
Personally, I can imagine the following dialogue between the EU officials (EU) and the lobbyists of the homeopathic industry (LOHI):
EU: We are very sorry but, because of the toxicity of mercury, we will not allow any of it in medicines.
LOHI: But we have always used it and nobody has come to harm.
EU: We don’t know that, and we have to be strict.
LOHI: We appreciate your concern, but we use only very, very tiny amounts; they cannot cause harm.
EU: The law is the law!
LOHI: Actually, the vast majority of our products are so dilute that they do not contain a single molecule of the ingredient on the bottle.
EU: That’s interesting! In this case, they are not medicines and we will have to ban them.
LOHI: NO, no, no – you don’t understand. We potentise our medicines; this means that the ingredient that they no longer contain gets more and more powerful.
EU: Are you sure?
LOHI: Absolutely!
EU: In this case, we will ban not just your mercury products but all your phony remedies. Because either science is right and they are fraudulent, or you are correct and they are dangerous.
No, I don’t want to put you off your breakfast… but you probably have seen so many pictures of attractive athletes with cupping marks and read articles about the virtues of this ancient therapy, that I feel I have to put this into perspective:
I am sure you agree that this is slightly less attractive. But, undeniably, these are also cupping marks. So, if you read somewhere that this treatment is entirely harmless, take it with a pinch of salt.
Cupping has existed for centuries in most cultures, and there are several variations of the theme. We differentiate between wet and dry cupping. The above picture is of wet cupping gone wrong. What the US Olympic athletes currently seem to be so fond of is dry cupping.
The principles of both forms are similar. In dry cupping, a vacuum cup is placed over the skin which provides enough suction to create a circular bruise. Eventually the vacuum diminishes, and the cup falls off; what is left is the mark. In wet cupping, the procedure is much the same, except that the skin is injured before the cup is placed. The suction then pulls out a small amount of blood. Obviously the superficial injury can get infected, and that is what we see on the above picture.
In the homeopathic hospital where I worked ~40 years ago, we did a lot of both types of cupping. We used it mostly for musculoskeletal pain. Our patients responded well.
But why? How does cupping work?
The answer is probably more complex than you expect. It clearly has a significant placebo effect. Athletes are obviously very focussed on their body, and they are therefore the ideal placebo-responders. Evidently, my patients 40 years ago also responded to all types of placebos, even to the homeopathic placebos which they received ‘en masse’.
But there might be other mechanisms as well. A TCM practitioner will probably tell you that cupping unblocks the energy flow in our body. This might sound very attractive to athletes or consumers, and therefore could even enhance the placebo response, but it is nevertheless nonsense.
The most plausible mode of action is ‘counter-irritation’: if you have a pain somewhere, a second pain elsewhere in your body can erase the original pain. You might have a headache, for instance, and if you accidentally hit your thumb with a hammer, the headache is gone, at least for a while. Cupping too would cause mild to moderate pain, and this is a distraction from the muscular pain the athletes aim to alleviate.
When I employed cupping 40 years ago, there was no scientific evidence testing its effects. Since a few years, however, clinical trials have started appearing. Many are from China, and I should mention that TCM studies from China almost never report a negative result. According to the Chinese, TCM (including cupping) works for everything. More recently,also some trials from other parts of the world have emerged. They have in common with the Chinese studies that they tend to report positive findings and that they are of very poor quality. (One such trial has been discussed previously on this blog.) In essence, this means that we should not rely on their conclusions.
A further problem with clinical trails of cupping is that it is difficult, if not impossible, to control for the significant placebo effects that this treatment undoubtedly generates. There is no placebo that could mimic all the features of real cupping in clinical trials; and there is no easy way to blind either the patient or the therapist.
So, we are left with an ancient treatment backed by a host of recent but flimsy studies and a growing craze for cupping fuelled by the Olympic games. What can one conclude in such a situation?
Personally, I would, whenever possible, recommend treatments that work beyond a placebo effect, because the placebo response tends to be unreliable and is usually of short duration – and I am not at all sure that cupping belongs into this category. I would also avoid wet cupping, because it can cause substantial harm. Finally, I would try to keep healthcare costs down; cupping itself is cheap but the therapist’s time might be expensive.
In a nutshell: would I recommend cupping? No, not any more than using a hammer for counter irritation! Will the Olympic athletes care a hoot about my recommendations? No, probably not!
The aim of a new meta-analysis was to estimate the clinical effectiveness and safety of acupuncture for amnestic mild cognitive impairment (AMCI), the transitional stage between the normal memory loss of aging and dementia. Randomised controlled trials (RCTs) of acupuncture versus medical treatment for AMCI were identified using six electronic databases.
Five RCTs involving a total of 568 subjects were included. The methodological quality of the RCTs was generally poor. Participants receiving acupuncture had better outcomes than those receiving nimodipine with greater clinical efficacy rates (odds ratio (OR) 1.78, 95% CI 1.19 to 2.65; p<0.01), mini-mental state examination (MMSE) scores (mean difference (MD) 0.99, 95% CI 0.71 to 1.28; p<0.01), and picture recognition score (MD 2.12, 95% CI 1.48 to 2.75; p<0.01). Acupuncture used in conjunction with nimodipine significantly improved MMSE scores (MD 1.09, 95% CI 0.29 to 1.89; p<0.01) compared to nimodipine alone. Three trials reported adverse events.
The authors concluded that acupuncture appears effective for AMCI when used as an alternative or adjunctive treatment; however, caution must be exercised given the low methodological quality of included trials. Further, more rigorously designed studies are needed.
Meta-analyses like this one are, in my view, perfect examples for the ‘rubbish in, rubbish out’ principle of systematic reviews. This may seem like an unfair statement, so let me justify it by explaining the shortfalls of this specific paper.
The authors try to tell us that their aim was “to estimate the clinical effectiveness and safety of acupuncture…” While it might be possible to estimate the effectiveness of a therapy by pooling the data of a few RCTs, it is never possible to estimate its safety on such a basis. To conduct an assessment of therapeutic safety, one would need sample sizes that go two or three dimensions beyond those of RCTs. Thus safety assessments are best done by evaluating the evidence from all the available evidence, including case-reports, epidemiological investigations and observational studies.
The authors tell us that “two studies did not report whether any adverse events or side effects had occurred in the experimental or control groups.” This is a common and serious flaw of many acupuncture trials, and another important reason why RCTs cannot be used for evaluating the risks of acupuncture. Too many such studies simply don’t mention adverse effects at all. If they are then submitted to systematic reviews, they must generate a false positive picture about the safety of acupuncture. The absence of adverse effects reporting is a serious breach of research ethics. In the realm of acupuncture, it is so common, that many reviewers do not even bother to discuss this violation of medical ethics as a major issue.
The authors conclude that acupuncture is more effective than nimodipine. This sounds impressive – unless you happen to know that nimodipine is not supported by good evidence either. A Cochrane review provided no convincing evidence that nimodipine is a useful treatment for the symptoms of dementia, either unclassified or according to the major subtypes – Alzheimer’s disease, vascular, or mixed Alzheimer’s and vascular dementia.
The authors also conclude that acupuncture used in conjunction with nimodipine is better than nimodipine alone. This too might sound impressive – unless you realise that all the RCTs in question failed to control for the effects of placebo and the added attention given to the patients. This means that the findings reported here are consistent with acupuncture itself being totally devoid of therapeutic effects.
The authors are quite open about the paucity of RCTs and their mostly dismal methodological quality. Yet they arrive at fairly definitive conclusions regarding the therapeutic value of acupuncture. This is, in my view, a serious mistake: on the basis of a few poorly designed and poorly reported RCTs, one should never arrive at even tentatively positive conclusion. Any decent journal would not have published such misleading phraseology, and it is noteworthy that the paper in question appeared in a journal that has a long history of being hopelessly biased in favour of acupuncture.
Any of the above-mentioned flaws could already be fatal, but I have kept the most serious one for last. All the 5 RCTs that were included in the analyses were conducted in China by Chinese researchers and published in Chinese journals. It has been shown repeatedly that such studies hardly ever report anything other than positive results; no matter what conditions is being investigated, acupuncture turns out to be effective in the hands of Chinese trialists. This means that the result of such a study is clear even before the first patient has been recruited. Little wonder then that virtually all reviews of such trials – and there are dozens of then – arrive at conclusions similar to those formulated in the paper before us.
As I already said: rubbish in, rubbish out!
