MD, PhD, FMedSci, FRSB, FRCP, FRCPEd.

false positive

A single, tiny mosquito can make my life a misery. It can rob me of a night’s sleep and turn me into a frantic lunatic. But now there is a remedy that, according to its manufacturer, makes my mosquito-phobia a distant memory. Mosquito-maniacs like myself can finally breathe a sigh of relief!

According to the manufacturer’s web-site, Mozi-Q is formula to reduce the frequency of bites as well as the reactions that people have to bites. No more itching and big red bumps! No more smelly sprays or stinky coils…what a great ally for camping, golfing, hiking, biking. This could revolutionize the whole outdoor experience! Some of the product’s features include:

  • It works within 30 minutes of taking it.
  • There are no side effects.
  • It works on other bugs aside from mosquitoes like ticks and head lice.
  • Product can be taken every 3-5 hours starting right before you go outside.
  • There are no contraindications.
  • Homeopathic medicine is by definition non-toxic…

Mozi-Q is a formula containing five homeopathic remedies:

  • Staphysagria
  • Ledum palustre
  • Urtica urens
  • Cedron 
  • Grindelia

They are in low C and D potencies, thereby acting at the physical level for their common indication, to reduce the frequency and severity of insect bites….

I am sure that most readers will, by now, ask themselves: is there any good evidence for these claims? The manufacturer’s site is pretty affirmative:

In the ’60s a homeopath by the name of HR. Trexler studied Staphysagria for its effectiveness at preventing mosquito bites. In a study of 421 subjects over a 4 year period, he found this remedy to be 90% effective…We have tested this remedy in our clinic over four mosquito seasons and found the response from the public confirmatory of Trexler’s findings.

Sounds great? Yes, but it turns out that the Trexler trial did not test the mixture contained in Mozi-Q at all; it used just one of its ingredients. Moreover, it seemed to have lacked a control group and therefore constitutes no reliable evidence. And the manufacturer’s own tests? I don’t know, they tell us nothing about them.

At this stage, the mosquito-phobe is disappointed. It seems to me that this product is not supported by sound evidence – more trick than treatment.

And why would this important? Because some people like me might lose a bit of sleep? No! It is important because mosquitos, ticks and other insects transmit diseases, some of which can be deadly. If someone claims that there is a preparation which protects us from insect-bites, some consumers will inevitably trust this claim. And this would not just be unfortunate; it could be life-threatening.

Swiss chiropractors have just published a clinical trial to investigate outcomes of patients with radiculopathy due to cervical disk herniation (CDH). All patients had neck pain and dermatomal arm pain; sensory, motor, or reflex changes corresponding to the involved nerve root and at least one positive orthopaedic test for cervical radiculopathy were included. CDH was confirmed by magnetic resonance imaging. All patients received regular neck manipulations.

Baseline data included two pain numeric rating scales (NRSs), for neck and arm, and the Neck Disability Index (NDI). At two, four and twelve weeks after the initial consultation, patients were contacted by telephone, and the data for NDI, NRSs, and patient’s global impression of change were collected. High-velocity, low-amplitude thrusts were administered by experienced chiropractors. The proportion of patients reporting to feel “better” or “much better” on the patient’s global impression of change scale was calculated. Pre-treatment and post-treatment NRSs and NDIs were analysed.

Fifty patients were included. At two weeks, 55.3% were “improved,” 68.9% at four and 85.7% at twelve weeks. Statistically significant decreases in neck pain, arm pain, and NDI scores were noted at 1 and 3 months compared with baseline scores. 76.2% of all sub-acute/chronic patients were improved at 3 months.

The authors concluded that most patients in this study, including sub-acute/chronic patients, with symptomatic magnetic resonance imaging-confirmed CDH treated with spinal manipulative therapy, reported significant improvement with no adverse events.

In the presence of disc herniation, chiropractic manipulations have been described to cause serious complications. Some experts therefore believe that CDH is a contra-indication for spinal manipulation. The authors of this study imply, however, that it is not – on the contrary, they think it is an effective intervention for CDH.

One does not need to be a sceptic to notice that the basis for this assumption is less than solid. The study had no control group. This means that the observed effect could have been due to:

a placebo response,

the regression towards the mean,

the natural history of the condition,

concomitant treatments,

social desirability,

or other factors which have nothing to do with the chiropractic intervention per se.

And what about the interesting finding that no adverse-effects were noted? Does that mean that the treatment is safe? Sorry, but it most certainly does not! In order to generate reliable results about possibly rare complications, the study would have needed to include not 50 but well over 50 000 patients.

So what does the study really tell us? I have pondered over this question for some time and arrived at the following answer: NOTHING!

Is that a bit harsh? Well, perhaps yes. And I will revise my verdict slightly: the study does tell us something, after all – chiropractors tend to confuse research with the promotion of very doubtful concepts at the expense of their patients. I think, there is a name for this phenomenon: PSEUDO-SCIENCE.

Researchers from the ‘Complementary and Integrative Medicine Research, Primary Medical Care, University of Southampton’ conducted a study of Professional Kinesiology Practice (PKP) What? Yes, PKP! This is a not widely known alternative method.

According to its proponents, it is unique and a complete kinesiology system… It was developed by a medical doctor, Dr Bruce Dewe and his wife Joan Dewe in the 1980s and has been taught since then in over 16 countries around the world with great success… Kinesiology is a unique and truly holistic science and on the cutting edge of energy medicine. It uses muscle monitoring as a biofeedback system to identify the underlying cause of blockage from the person’s subconscious mind via the nervous system. Muscle monitoring is used to access information from the person’s “biocomputer”, the brain, in relation to the problem or issue and also guides the practitioner to find the priority correction in order to stimulate the person’s innate healing capacity and support their physiology to return to normal function. Kinesiology is unique as it looks beyond symptoms. It recognizes the flows of energy within the body not only relate to the muscles but to every tissue and organ that make the human body a living ever changing organism. These energy flows can be evaluated by testing the function of the muscles, which in turn reflect the body’s overall state of structural, chemical, emotional and spiritual balance. In this way kinesiology taps into energies that the more conventional modalities overlook and helps remove all the guesswork, doubt and hard work of subjective diagnostics. This is a revolutionary way to communicate with the body/mind connection. Through muscle monitoring and the use of over 300 fingermodes we can detect and correct the cause of the problem and effect a long lasting change for better health and wellbeing. Our posture could be considered to be the visual display unit from our internal bio-computer. Our posture / life energy improves as we upgrade the way we respond to life’s constant challenges and demands.

You do not understand? Let me make it crystal clear by citing another PKP-site:

PKP is a phenomenological practice – this means practitioners use manual muscle testing to demonstrate to the client how much or how little they are able to move in relation to their problem. PKP practitioners have tests for more than 100 muscles, and dozens of other tests that they do so they can clearly show you how your movement is affected by your problem. This muscle story shows a person how their life is unfolding, and it also helps to guide on how to transcend the situation and design a future which is more in alignment with nature and the laws of the cosmos… PKP is about living life more wisely.

In case you still have not understood what PKP is, you might have to watch this youtube clip. And now that everyone knows what it is, let us have a look at the new study.

According to its authors, it was an exploratory, pragmatic single-blind, 3-arm randomised sham-controlled pilot trial with waiting list control (WLC) which was conducted in the setting of a UK private practice. Seventy participants scoring ≥4 on the Roland and Morris Disability Questionnaire (RMDQ) were randomised to real or sham PKP receiving one treatment weekly for 5 weeks or a WLC. WLC’s were re-randomised to real or sham after 6 weeks. The main outcome measure was a change in RMDQ from baseline to end of 5 weeks of real or sham PKP.

The results show an effect size of 0.7 for real PKP which was significantly different to sham. Compared to WLC, both real and sham groups had significant RMDQ improvements. Practitioner empathy (CARE) and patient enablement (PEI) did not predict outcome; holistic health beliefs (CAMBI) did, though. The sham treatment appeared credible; patients did not guess treatment allocation. Three patients reported minor adverse reactions.

From these data, the authors conclude that real treatment was significantly different from sham demonstrating a moderate specific effect of PKP; both were better than WLC indicating a substantial non-specific and contextual treatment effect. A larger definitive study would be appropriate with nested qualitative work to help understand the mechanisms involved in PKP.

So, PKP has a small specific effect in addition to generating a sizable placebo-effect? Somehow, I doubt it! This was, according to its authors, a pilot study. Such an investigation should not evaluate the effectiveness of a treatment but the feasibility of the protocol. Even if we disregard this detail, I assume that the results indicate the effects of PKP to be essentially due to placebo. The small effect which the authors label as “specific” is, in my view, almost certainly caused by residual confounding and hidden biases.

One could also go one step further and say that any treatment that is shrouded in pseudo-scientific language and has zero plausibility is an ill-conceived candidate for a clinical trial of this nature. If it should be tested at all – and thus cost money, effort and patient-participation – a rigorous study should be designed and conducted not by apologists of the intervention but by more level-headed scientists.

In 2010, NICE recommended acupuncture for chronic low back pain (cLBP). Acupuncturists were of course delighted; the British Acupuncture Council, for instance, stated that they fully support NICE’s (National Institute for Health and Clinical Excellence) decision that acupuncture be made available on the NHS for chronic lower back pain. Traditional acupuncture has been used for over 2,000 years to alleviate back pain and British Acupuncture Council members have for many many years been successfully treating patients for this condition either in private practice or working within the NHS. In effect, therefore, these new guidelines are a rubber stamp of the positive work already being undertaken as well as an endorsement of the wealth of research evidence now available in this area.

More critical experts, however, tended to be surprised about this move and doubted that the evidence was strong enough for a positive recommendation. Now a brand-new meta-analysis sheds more light on this important issue.

Its aim was to determine the effectiveness of acupuncture as a therapy for cLBP. The authors found 13 RCTs which matched their inclusion criteria. Their results show that, compared with no treatment, acupuncture achieved better outcomes in terms of pain relief, disability recovery and better quality of life. These effects were, however, not observed when real acupuncture was compared to sham acupuncture. Acupuncture achieved better outcomes when compared with other treatments. No publication bias was detected.

The authors conclude that acupuncture is an effective treatment for chronic low back pain, but this effect is likely to be produced by the nonspecific effects of manipulation.

In plain English, this means that the effects of acupuncture on cLBP are most likely due to placebo. Should NICE be recommending placebo-treatments and have the tax payer foot the bill? I think I can leave it to my readers to answer this question.

Hot flushes are a big problem; they are not life-threatening, of course, but they do make life a misery for countless menopausal women. Hormone therapy is effective, but many women have gone off the idea since we know that hormone therapy might increase their risk of getting cancer and cardiovascular disease. So, what does work and is also risk-free? Acupuncture?

Together with researchers from Quebec, we wanted to determine whether acupuncture is effective for reducing hot flushes and for improving the quality of life of menopausal women. We decided to do this in form of a Cochrane review which was just published.

We searched 16 electronic databases in order to identify all relevant studies and included all RCTs comparing any type of acupuncture to no treatment/control or other treatments. Sixteen studies, with a total of 1155 women, were eligible for inclusion. Three review authors independently assessed trial eligibility and quality, and extracted data. We pooled data where appropriate.

Eight studies compared acupuncture versus sham acupuncture. No significant difference was found between the groups for hot flush frequency, but flushes were significantly less severe in the acupuncture group, with a small effect size. There was substantial heterogeneity for both these outcomes. In a post hoc sensitivity analysis excluding studies of women with breast cancer, heterogeneity was reduced to 0% for hot flush frequency and 34% for hot flush severity and there was no significant difference between the groups for either outcome. Three studies compared acupuncture with hormone therapy, and acupuncture turned out to be associated with significantly more frequent hot flushes. There was no significant difference between the groups for hot flush severity. One study compared electro-acupuncture with relaxation, and there was no significant difference between the groups for either hot flush frequency or hot flush severity. Four studies compared acupuncture with waiting list or no intervention. Traditional acupuncture was significantly more effective in reducing hot flush frequency, and was also significantly more effective in reducing hot flush severity. The effect size was moderate in both cases.

For quality of life measures, acupuncture was significantly less effective than HT, but traditional acupuncture was significantly more effective than no intervention. There was no significant difference between acupuncture and other comparators for quality of life. Data on adverse effects were lacking.

Our conclusion: We found insufficient evidence to determine whether acupuncture is effective for controlling menopausal vasomotor symptoms. When we compared acupuncture with sham acupuncture, there was no evidence of a significant difference in their effect on menopausal vasomotor symptoms. When we compared acupuncture with no treatment there appeared to be a benefit from acupuncture, but acupuncture appeared to be less effective than HT. These findings should be treated with great caution as the evidence was low or very low quality and the studies comparing acupuncture versus no treatment or HT were not controlled with sham acupuncture or placebo HT. Data on adverse effects were lacking.

I still have to meet an acupuncturist who is not convinced that acupuncture is not an effective treatment for hot flushes. You only need to go on the Internet to see the claims that are being made along those lines. Yet this review shows quite clearly that it is not better than placebo. It also demonstrates that studies which do suggest an effect do so because they fail to adequately control for a placebo response. This means that the benefit patients and therapists observe in routine clinical practice is not due to the acupuncture per se, but to the placebo-effect.

And what could be wrong with that? Quite a bit, is my answer; here are just 4 things that immediately spring into my mind:

1) Arguably, it is dishonest and unethical to use a placebo on ill patients in routine clinical practice and charge for it pretending it is a specific and effective treatment.

2) Placebo-effects are unreliable, small and usually of short duration.

3) In order to generate a placebo-effect, I don’t need a placebo-therapy; an effective one administered with compassion does that too (and generates specific effects on top of that).

4) Not all placebos are risk-free. Acupuncture, for instance, has been associated with serious complications.

The last point is interesting also in the context of our finding that the RCTs analysed failed to mention adverse-effects. This is a phenomenon we observe regularly in studies of alternative medicine: trialists tend to violate the most fundamental rules of research ethics by simply ignoring the need to report adverse-effects. In plain English, this is called ‘scientific misconduct’. Consequently, we find very little published evidence on this issue, and enthusiasts claim their treatment is risk-free, simply because no risks are being reported. Yet one wonders to what extend systematic under-reporting is the cause of that impression!

So, what about the legion of acupuncturists who earn a good part of their living by recommending to their patients acupuncture for hot flushes?

They may, of course, not know about the evidence which shows that it is not more than a placebo. Would this be ok then? No, emphatically no! All clinicians have a duty to be up to date regarding the scientific evidence in relation to the treatments they use. A therapist who does not abide by this fundamental rule of medical ethics is, in my view, a fraud. On the other hand, some acupuncturists might be well aware of the evidence and employ acupuncture nevertheless; after all, it brings good money! Well, I would say that such a therapist is a fraud too.

Did I previously imply that osteopaths are not very research-active? Shame on me!

Here are two brand-new studies by osteopaths and they both seem to show that their treatments work.

Impressed?

Well, perhaps we better have a closer look at them before we start praising osteopathic research efforts.

THE FIRST STUDY

Researchers from the ‘European Institute for Evidence Based Osteopathic Medicine’ in Chieti, Italy, investigated the effect of  osteopathic manipulative therapy (OMT) on the length of hospital-stay (LOHS) in premature infants. They conducted an RCT on 110 preterm newborns admitted to a single specialised unit. Thus the subjects with a gestational age between 28 and 38 weeks were randomized to receive either just routine care, or routine care with OMT for the period of hospitalization. Endpoints were differences in LOHS and daily weight gain. The results showed a mean difference in LOHS between the OMT and the control group: -5.906 days (95% C.I. -7.944, -3.869; p<0.001). However, OMT was not associated with any change in daily weight gain.

The authors’ conclusion was bold: OMT may have an important role in the management of preterm infants hospitalization.

THE SECOND STUDY

The second investigation suggested similarly positive effects of OMT on LOHS in a different setting. Using a retrospective cohort study, US osteopaths wanted to determine whether there is a relationship between post-operative use of OMT and post-operative outcomes in gastrointestinal surgical patients, including time to flatus, clear liquid diet, and bowel movement [all indicators for the length of the post-operative ileus] as well as LOHS. They thus assessed the records of 55 patients who underwent a major gastrointestinal operation in a hospital that had been routinely offering OMT to its patients. The analyses showed that 17 patients had received post-operative OMT and 38 had not.The two groups were similar in terms of all variables the researchers managed to assess. The time to bowel movement and to clear liquid diet did not differ significantly between the groups. The mean time to flatus was 4.7 days in the non-OMT group and 3.1 days in the OMT group (P=.035). The mean post-operative hospital LOHS was also reduced significantly with OMT, from 11.5 days in the non-OMT group to 6.1 days in the OMT group (P=.006).

The authors concluded that OMT applied after a major gastrointestinal operation is associated with decreased time to flatus and decreased postoperative hospital LOHS.

WHAT SHOULD WE MAKE OF THESE RESULTS?

Some people may have assumed that OMT is for bad backs; these two studies imply, however, that it can do much more. If the findings are correct, they have considerable implications: shortening the time patients have to spend in hospital would not only decrease individual suffering, it would also save us all tons of money! But do these results hold water?

The devil’s advocate in me cannot help but being more than a little sceptical. I fail to see how OMT might shorten LOHS; it just does not seem plausible! Moreover, some of the results seem too good to be true. Could there be any alternative explanations for the observed findings?

The first study, I think, might merely demonstrate that more time spent handling  premature babies provides a powerful developmental stimulus. Therefore the infants are quicker ready to leave hospital compared to those children who did not receive this additional boost. But the effect might not at all be related to OMT per se; if, for instance, the parents had handled their children for the same amount of time, the outcome would probably have been quite similar, possibly even better.

The second study is not an RCT and therefore it tells us little about cause and effect. We might speculate, for instance, that those patients who elected to have OMT were more active, had lived healthier lives, adhered more rigorously to a pre-operative diet, or differed in other variables from those patients who chose not to bother with OMT. Again, the observed difference in the duration of the post-operative ileus and consequently the LOHS would be entirely unrelated to OMT.

I suggest therefore to treat these two studies with more than just a pinch of salt. Before hospitals all over the world start employing osteopaths right, left and centre in order to shorten their average LOHS, we might be well advised to plan and conduct a trial that avoids the pitfalls of the research so far. I would bet a fiver that, once we do a proper independent replication, we will find that both investigations did, in fact, generate false positive results.

My conclusion from all this is simple: RESEARCH CAN SOMETIMES BE MISLEADING, AND POOR QUALITY RESEARCH IS ALMOST INVARIABLY MISLEADING.

A recently published study by Danish researchers aimed at comparing the effectiveness of a patient education (PEP) programme with or without the added effect of chiropractic manual therapy (MT) to a minimal control intervention (MCI). Its results seem to indicate that chiropractic MT is effective. Is this the result chiropractors have been waiting for?

To answer this question, we need to look at the trial and its methodology in more detail.

A total of 118 patients with clinical and radiographic unilateral hip osteoarthritis (OA) were randomized into one of three groups: PEP, PEP+ MT or MCI. The PEP was taught by a physiotherapist in 5 sessions. The MT was delivered by a chiropractor in 12 sessions, and the MCI included a home stretching programme. The primary outcome measure was the self-reported pain severity on an 11-box numeric rating scale immediately following the 6-week intervention period. Patients were subsequently followed for one year.

The primary analyses included 111 patients. In the PEP+MT group, a statistically and clinically significant reduction in pain severity of 1.9 points was noted compared to the MCI of 1.90. The number needed to treat for PEP+MT was 3. No difference was found between the PEP and the MCI groups. At 12 months, the difference favouring PEP+MT was maintained.

The authors conclude that for primary care patients with osteoarthritis of the hip, a combined intervention of manual therapy and patient education was more effective than a minimal control intervention. Patient education alone was not superior to the minimal control intervention.

This is an interesting, pragmatic trial with a result suggesting that chiropractic MT in combination with PEP is effective in reducing the pain of hip OA. One could easily argue about the small sample size, the need for independent replication etc. However, my main concern is the fact that the findings can be interpreted in not just one but in at least two very different ways.

The obvious explanation would be that chiropractic MT is effective. I am sure that chiropractors would be delighted with this conclusion. But how sure can we be that it would reflect the truth?

I think an alternative explanation is just as (possibly more) plausible: the added time, attention and encouragement provided by the chiropractor (who must have been aware what was at stake and hence highly motivated) was the effective element in the MT-intervention, while the MT per se made little or no difference. The PEP+MT group had no less than 12 sessions with the chiropractor. We can assume that this additional care, compassion, empathy, time, encouragement etc. was a crucial factor in making these patients feel better and in convincing them to adhere more closely to the instructions of the PEP. I speculate that these factors were more important than the actual MT itself in determining the outcome.

In my view, such critical considerations regarding the trial methodology are much more than an exercise in splitting hair. They are important in at least two ways.

Firstly, they remind us that clinical trials, whenever possible, should be designed such that they allow only one interpretation of their results. This can sometimes be a problem with pragmatic trials of this nature. It would be wise, I think, to conduct pragmatic trials only of interventions which have previously been proven to work.  To the best of my knowledge, chiropractic MT as a treatment for hip OA does not belong to this category.

Secondly, it seems crucial to be aware of such methodological issues and to consider them carefully before research findings are translated into clinical practice. If not, we might end up with  therapeutic decisions (or guidelines) which are quite simply not warranted.

I would not be in the least surprised, if chiropractic interest groups were to use the current findings for promoting chiropractic in hip-OA. But what, if the MT per se was ineffective, while the additional care, compassion and encouragement was? In this case, we would not need to recruit (and pay for) chiropractors and put up with the considerable risks chiropractic treatments can entail; we would merely need to modify the PE programme such that patients are better motivated to adhere to it.

As it stands, the new study does not tell us much that is of any practical use. In my view, it is a pragmatic trial which cannot readily be translated into evidence-based practice. It might get interpreted as good news for chiropractic but, in fact, it is not.

Ignaz von Peczely (1826-1911), a Hungarian physician, got the idea for iridology (or iris-diagnosis) more than a century ago, after seeing streaks in the iris of a man he was treating for a broken leg, and similar phenomena the iris of an owl whose leg von Peczely had broken many years before. He subsequently became convinced that his method was able to distinguish between healthy organs and those that are overactive, inflamed, or distressed. Iridology became internationally known when US chiropractors began adopting this method in their clinical practice. In the United States, most insurance programs do not cover iridology but, in some European countries, they often do. In Germany, for instance, 80% of the Heilpraktiker (non-medically qualified health practitioners) practice iridology.

Iridologists claim to be able to diagnose the health status of an individual, medical conditions or predispositions to disease through abnormalities of pigmentation in the iris. The popularity of iridology renders it necessary to ask whether this method is valid.

The aim of my systematically review from 1999 was to critically evaluate all available, reliable tests of iridology as a diagnostic tool. Four case control studies were included; these are investigations where iridologists are asked to tell by looking at the iris of individuals whether that person does or does not have a certain condition. The majority of these studies suggested that iridology is not a valid diagnostic method. Back then, I concluded that “the validity of iridology as a diagnostic tool is not supported by scientific evaluations. Patients and therapists should be discouraged from using this method.”

Since the publication of my article, several further studies have emerged:

One German team conducted a study investigating the applicability of iridology as a screening method for colorectal cancer. Digital color slides were obtained from both eyes of 29 patients with histologically diagnosed colorectal cancer and from 29 age- and gender-matched healthy control subjects. The slides were presented in random order to acknowledged iridologists without knowledge of the number of patients in the two categories. The iridologists correctly detected 51.7% and 53.4%, respectively, of the patients’ slides; therefore, the likelihood was statistically no better than chance. Sensitivity was, respectively, 58.6% and 55.2%, and specificity was 44.8% and 51.7%. The authors’ conclusion was blunt: “Iridology had no validity as a diagnostic tool for detecting colorectal cancer in this study.”

A study from South Africa aimed to determine the efficacy of iridology in the identification of moderate to profound sensorineural hearing loss in adolescents. A controlled trial was conducted with an iridologist, blind to the actual hearing status of participants, analysing the irises of participants with and without hearing loss. Fifty hearing impaired and fifty normal hearing subjects, between the ages of 15 and 19 years, controlled for gender, participated in the study. An experienced iridologist analysed the randomised set of participants’ irises. A 70% correct identification of hearing status was obtained with a false negative rate of 41% compared to a 19% false positive rate. The respective sensitivity and specificity rates therefore were 59% and 81%. The authors of this investigation concluded that “iridological analysis of hearing status indicated a statistically significant relationship to actual hearing status (P < 0.05). Although statistically significant sensitivity and specificity rates for identifying hearing loss by iridology were not comparable to those of traditional audiological screening procedures.”

A further German study investigated the value of iridology as a diagnostic tool in detecting some common cancers. One hundred ten subjects were enrolled; 68 subjects had histologically proven cancers of the breast, ovary, uterus, prostate, or colorectum, and 42 were cancer-free controls. All subjects were examined by an experienced practitioner of iridology, who was unaware of their medical details. He was allowed to suggest up to five diagnoses for each subject and his results were then compared with each subject’s medical diagnosis to determine the accuracy of iridology in detecting malignancy. Iridology identified the correct diagnosis in only 3 cases (sensitivity, 0.04). The authors concluded that “iridology was of no value in diagnosing the cancers investigated in this study.”

Based on these results it is impossible, I think, to claim that iridology is a valid or useful diagnostic tool. As there is no anatomical or physiological basis for its assumptions, iridology is not biologically plausible. Furthermore, the available clinical evidence does not support its validity as a diagnostic tool. In other words, iridology is bogus. This statement is in sharp contract to the information consumers receive about the method on uncounted websites, books, articles, etc. One website picked at random provides the following information:

The iris reveals changing conditions of every part and organ of the body. Every organ and part of the body is represented in the iris in a well defined area. In addition, through various marks, signs, and discoloration in the iris, nature reveals inherited weaknesses and strengths.

By means of this art / science, an iridologist (one who studies the coloration and fiber structure of the eye) can tell an individual his/her inherited and acquired tendencies towards health and disease, his current condition in general, and the state of every organ in particular.

Iridology cannot detect a specific disease, but, can tell an individual if they have over or under activity in specific areas of the body. For example, an under-active pancreas might indicate a diabetic condition.

Another source claims:

The underlying platform of iridology is that that eyes act as a ‘window’ to a person’s health & well being. This ‘window’ enables the practitioner to see whether areas or organs within the body are healthy, inflamed or ‘over active’. It also enables them to assess a person’s past/ possible future health problems & consider if the patient has a susceptibility to certain diseases. It is important to understand that iridology is simply a method of diagnosis & analysis.

You may well think that none of this really matters. Who cares whether iridology is bogus or not! I would argue that it does matter. Bogus methods cost money that could be better spent elsewhere. More importantly, false positive and false negative diagnoses generated by bogus diagnostic methods can put lives at risk.

But there is a more general and perhaps more crucial point here: alternative medicine is an area where people far too easily get away with ignoring the published evidence and scientific consensus. In the last two decades, I have seen many alternative modalities getting scientifically dis-proven; not in a single such instance can I remember that the corresponding alternative practitioners and their professional organisations took any notice of this fact, and not once did I notice that their practice had changed.

If research is  systematically ignored, it becomes a useless appendix. More importantly, progress is then stifled to the detriment of all our best interests.

Indian homeopaths recently published a clinical trial aimed at evaluating homeopathic treatment in the management of diabetic polyneuropathy. The condition affects many diabetic patients; its symptoms include tingling, numbness, burning sensation in the feet and pain, particularly at night. The best treatment consists of adequate metabolic control of the underlying diabetes. The pain can be severe often does not respond adequately to conventional pain-killers. It is therefore obvious that any new, effective treatment would be more than welcome.

The new trial  is a prospective observational study which was carried out from October 2005 to September 2009 by the Indian Central Council for Research in Homeopathy at its five Institutes. Patients suffering diabetic polyneuropathy (DPN) were screened and enrolled in the study, if they fulfilled the inclusion and exclusion criteria. The Diabetic Distal Symmetric Polyneuropathy Symptom Score (DDSPSS), developed by the Council, served as the primary outcome measure.

A total of 15 homeopathic medicines were identified after repertorizing the nosological symptoms and signs of the disease. The appropriate constitutional medicine was selected and prescribed in the 30, 200 and 1 M potencies on an individualized basis. Patients were followed up for 12 months.

Of 336 diabetics enrolled in the study, 247 patients who attended at least three follow-up appointments and baseline nerve conduction studies were included in the analysis. A statistically significant improvement in DDSPSS total score was found at 12 months. Most objective measures did not show significant improvements. Lycopodium clavatum (n = 132), Phosphorus (n = 27) and Sulphur (n = 26) were the most frequently prescribed homeopathic remedies.

From these results, the authors concluded that: “homeopathic medicines may be effective in managing the symptoms of DPN patients.”

Does this study tell us anything worth knowing? The short answer to this question, I am afraid, is NO.

Its weaknesses are all too obvious:

1) There was no control group.

2) Patients who did not come back to the follow-up appointments – presumably because they were not satisfied – were excluded from the analyses. The average benefit reported is thus likely to be a cherry-picked false positive result.

3) The primary outcome measure was not validated.

4) The observed positive effect on subjective symptoms could be due to several factors which are entirely unrelated to the homeopathic treatments’ e.g. better metabolic control, regression towards the mean, or social desirability.

Anyone who had seen the protocol of this study would have predicted the result; I see no way that such a study does not generate an apparently positive outcome. In other words, conducting the investigation was superfluous, which means that the patients’ participation was in vain; and this, in turn, means that the trial was arguably unethical.

This might sound a bit harsh, but I am entirely serious: deeply flawed research should not happen. It is a waste of scarce resources and patients’ tolerance; crucially, it has a powerful potential to mislead us and to set back our efforts to improve health care. All of this is unethical.

The problem of research which is so poor that it crosses the line into being unethical is, of course, not confined to homeopathy. In my view, it is an important issue in much of alternative medicine and quite possibly in conventional medicine as well. Over the years, several mechanisms have been put in place to prevent or at least minimize the problem, for instance, ethic committees and peer-review. The present study shows, I think, that these mechanisms are fragile and that, sometimes, they fail altogether.

In their article, the authors of the new homeopathic study suggest that more investigations of homeopathy for diabetic polyneuropathy should be done. However, I suggest almost precisely the opposite: unethical research of this nature should be prevented, and the existing mechanisms to achieve this aim must be strengthened.

Neck pain is a common problem which is often far from easy to treat. Numerous therapies are being promoted but few are supported by good evidence. Could yoga be the solution?

The aim of a brand-new RCT was to evaluate the effectiveness of Iyengar yoga for chronic non-specific neck pain. Patients were randomly assigned to either yoga or exercise. The yoga group attended a 9-week yoga course, while the exercise group received a self-care manual on home-based exercises for neck pain. The primary outcome measure was neck pain. Secondary outcome measures included functional disability, pain at motion, health-related quality of life, cervical range of motion, proprioceptive acuity, and pressure pain threshold. Fifty-one patients participated in the study: yoga (n = 25), exercise (n = 26). At the end of the treatment phase, patients in the yoga group reported significantly less neck pain compared as well as less disability and better mental quality of life compared with the exercise group. Range of motion and proprioceptive acuity were improved and the pressure pain threshold was elevated in the yoga group.

The authors draw the following conclusion: “Yoga was more effective in relieving chronic nonspecific neck pain than a home-based exercise program. Yoga reduced neck pain intensity and disability and improved health-related quality of life. Moreover, yoga seems to influence the functional status of neck muscles, as indicated by improvement of physiological measures of neck pain.”

I’d love to agree with the authors and would be more than delighted, if an effective treatment for neck pain had been identified. Yoga is fairly safe and inexpensive; it promotes a generally healthy life-style, and is attractive to many patients; it has thus the potential to help thousands of suffering individuals. However, I fear that things might not be quite as rosy as the authors of this trial seem to believe.

The principle of an RCT essentially is that two groups of patients receive two different therapies and that any difference in outcome after the treatment phase is attributable to the therapy in question. Unfortunately, this is not the case here. One does not need to be an expert in critical thinking to realise that, in the present study, the positive outcome might be unrelated to yoga. For instance, it could be that the unsupervised home exercises were carried out wrongly and thus made the neck pain worse. In this case, the difference between the two treatment groups might not have been caused by yoga at all. A second possibility is that the yoga-group benefited not from the yoga itself but from the attention given to these patients which the exercise-group did not have. A third explanation could be that the yoga teachers were very kind to their patients, and that the patients returned their kindness by pretending to have less symptoms or exaggerating their improvements. In my view the most likely cause of the results seen in this study is a complex mixture of all the options just mentioned.

This study thus teaches us two valuable lessons: 1) whenever possible, RCTs should be designed such that a clear attribution of cause and effect is possible, once the results are on the table; 2) if cause and effect cannot be clearly defined, it is unwise to draw conclusions that are definite and have the potential to mislead the public.

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