Excessive eccentric exercise of inadequately conditioned skeletal muscle results in focal sites of injury within the muscle fibres. These injuries cause pain which usually is greatest about 72 hours after the exercise. This type of pain is called delayed-onset muscle soreness (DOMS) and provides an accessible model for studying the effects of various treatments that are said to have anaesthetic activities; it can easily be reproducibly generated without lasting harm or ethical concerns.
In so-called alternative medicine (SCAM) DOMS is employed regularly to test treatments which are promoted for pain management. Thus several acupuncture trials using this method have become available. Yet, the evidence for the effects of acupuncture on DOMS is inconsistent which begs the question whether across all trials an effects emerges.
The aim of this systematic review therefore was to explore the effects of acupuncture on DOMS. Studies investigating the effect of acupuncture on DOMS in humans that were published before March 2020 were obtained from 8 electronic databases. The affected muscles, groups, acupuncture points, treatment sessions, assessments, assessment times, and outcomes of the included articles were reviewed. The data were extracted and analysed via a meta-analysis.
A total of 15 articles were included, and relief of DOMS-related pain was the primary outcome. The meta-analysis showed that there were no significant differences between acupuncture and sham/control groups, except for acupuncture for DOMS on day 1 (total SMD = -0.62; 95% CI = -1.12∼0.11, P < 0.05) by comparing with control groups.
The authors concluded that acupuncture for DOMS exhibited very-small-to-small and small-to-moderate effects on pain relief for the sham and no acupuncture conditions, respectively. Evidence indicating the effects of acupuncture on DOMS was little because the outcome data during the follow-up were insufficient to perform an effective meta-analysis.
A mere glance at the Forrest plot reveals that acupuncture is unlikely to have any effect on DOMS at all. The very small average effect that does emerge originates mainly from one outlier, the 2008 study by Itoh et al. This trial was published by three acupuncturists from the Department of Clinical Acupuncture and Moxibustion, Meiji University of Integrative Medicine, Kyoto, Japan. It has numerous weaknesses, for instance there are just 10 volunteers in each group, and can therefore be safely discarded.
In essence, this means that there is no good evidence that acupuncture is effective at reducing pain caused by DOMS.
Tasuki is a sort of sash for holding up the sleeves on a kimono. It also retracts the shoulders and keeps the head straight up. By correcting the wearer’s posture, it might even prevent or treat neck pain. The greater the forward head posture, for example, the more frequent are neck problems. However, there is little clinical evidence to support or refute this hypothesis.
This study was conducted to determine whether Tasuki-style posture supporter improves neck pain compared to waiting-list. It was designed as an individually-randomized, open-label, waiting-list-controlled study. Adults with non-specific chronic neck pain who reported 10 points or more on modified Neck Disability Index (mNDI: range, 0-50; higher points indicate worse condition) were enrolled. Participants were randomly assigned 1:1 to the intervention group or to a waiting-list control group. The primary outcome was the change in mNDI at 1 week.
In total, 50 participants were enrolled. Of these participants, 26 (52%) were randomly assigned to the intervention group and 24 to the waiting-list. Attrition rate was low in both groups (1/50). The mean mNDI change score at 1 week was more favourable for Tasuki than waiting-list (between-group difference, -3.5 points (95% confidence interval (CI), -5.3 to -1.8); P = .0002). More participants (58%) had moderate benefit (at least 30% improvement) with Tasuki than with waiting-list (13%) (relative risk 4.6 (95% CI 1.5 to 14); risk difference 0.45 (0.22 to 0.68)).
The author concluded that this trial suggests that wearing Tasuki might moderately improve neck pain. With its low-cost, low-risk, and easy-to-use nature, Tasuki could be an option for those who suffer from neck pain.
In the previous two posts, we discussed how lamentably weak the evidence for acupuncture and spinal manipulation is regarding the management of pain such as ‘mechanical’ neck pain. Here we have a well-reported study with a poor design (no control for non-specific effects) which seems to suggest that simply wearing a Tasuki is just as effective as acupuncture or spinal manipulation.
What is the lesson from this collective evidence?
Is it that we should forget about acupuncture and spinal manipulation for chronic neck pain?
Or is it that poor trial designs generate unreliable evidence?
Or is it that any treatment, however daft, will generate positive outcomes, if the researchers are sufficiently convinced of its benefit?
Yes, I think so.
If you had chronic neck pain, would you rather have your neck manipulated, needles stuck into your body, or get a Tasuki? (Spoiler: Tasuki is risk-free, the other two treatments are not!)
As recently reported, the most thorough review of the subject showed that the evidence for acupuncture as a treatment for chronic pain is very weak. Yesterday, NICE published a draft report that seems to somewhat disagree with this conclusion (and today, this is being reported in most of the UK daily papers). The draft is now open to public consultation until 14 September 2020 and many of my readers might want to comment.
The draft report essentially suggests that people with chronic primary pain (CPP) should not get pain-medication of any type, but be offered supervised group exercise programmes, some types of psychological therapy, or acupuncture. While I understand that chronic pain should not be treated with long-term pain-medications – I did even learn this in medical school all those years ago – one might be puzzled by the mention of acupuncture.
But perhaps we need first ask, WHAT IS CPP? The NICE report informs us that CPP represents chronic pain as a condition in itself and which can’t be accounted for by another diagnosis, or where it is not the symptom of an underlying condition (this is known as chronic secondary pain). I find this definition most unsatisfactory. Pain is usually a symptom and not a disease. In many forms of what we now call CPP, an underlying disease does exist but might not yet be identifiable, I suspect.
The evidence on acupuncture considered for the draft NICE report included conditions like:
- neck pain,
- myofascial pain,
- radicular arm pain,
- shoulder pain,
- prostatitis pain,
- mechanical neck pain,
I find it debatable whether these pain syndromes can be categorised to be without an underlying diagnosis. Moreover, I find it problematic to lump them together as though they were one big entity.
The NICE draft document is huge and far too big to be assessed in a blog like mine. As it is merely a draft, I also see little point in evaluating it or parts of in detail. Therefore, my comments are far from detailed, very brief and merely focussed on pain (the draft NICE report considers several further outcome measures).
There is a separate document for acupuncture, from which I copy what I consider the key evidence:
Acupuncture versus sham acupuncture
Very low quality evidence from 13 studies with 1230 participants showed a clinically
important benefit of acupuncture compared to sham acupuncture at ≤3 months. Low quality
evidence from 2 studies with 159 participants showed a clinically important benefit of
acupuncture compared to sham acupuncture at ≤3 months.
Low quality evidence from 4 studies with 376 participants showed no clinically important
difference between acupuncture and sham acupuncture at >3 months. Moderate quality
evidence from 2 studies with 159 participants showed a clinically important benefit of
acupuncture compared to sham acupuncture at >3 months. Low quality evidence from 1
study with 61 participants showed no clinically important difference between acupuncture
and sham acupuncture at >3 months.
As acupuncture has all the features that make a perfect placebo (slightly invasive, mildly painful, exotic, involves touch, time and attention), I see little point in evaluating its efficacy through studies that make no attempt to control for placebo effects. This is why the sham-controlled studies are central to the question of acupuncture’s efficacy, no matter for what condition.
Reading the above evidence carefully, I fail to see how NICE can conclude that CPP patients should be offered acupuncture. I am sure that some readers will disagree and am looking forward to reading their comments.
This analysis was aimed at assessing the associations of acupuncture use with mortality, readmission and reoperation rates in hip fracture patients using a longitudinal population-based database. A retrospective matched cohort study was conducted using data for the years 1996-2012 from Taiwan’s National Health Insurance Research Database. Hip fracture patients were divided into:
- an acupuncture group consisting of 292 subjects who received at least 6 acupuncture treatments within 183 days of hip fracture,
- and a propensity score matched “no acupuncture” group of 876 subjects who did not receive any acupuncture treatment and who functioned as controls.
The two groups were compared using survival analysis and competing risk analysis.
Compared to non-treated subjects, subjects treated with acupuncture had
- a lower risk of overall death (hazard ratio (HR): 0.41, 95% confidence interval (CI): 0.24-0.73, p = 0.002),
- a lower risk of readmission due to medical complications (subdistribution HR (sHR): 0.64, 95% CI: 0.44-0.93, p = 0.019)
- and a lower risk of reoperation due to surgical complications (sHR: 0.62, 95% CI: 0.40-0.96, p = 0.034).
The authors concluded that postoperative acupuncture in hip fracture patients is associated with significantly lower mortality, readmission and reoperation rates compared with those of matched controls.
That’s a clear and neat finding; the question is, what does it mean?
Here are a few possibilities for consideration:
- As a result of having at least 6 acupuncture sessions, patients had lower rates of mortality, readmission and reoperation.
- As a result of having lower rates of mortality, readmission and reoperation, patients used acupuncture.
- As a result of some other factor, patients had both lower rates of mortality, readmission and reoperation and at least 6 sessions of acupuncture.
Which of the three possibilities is the most likely?
- Some enthusiasts might think that acupuncture makes you live longer. But does anyone truly believe it reduces the likelihood of needing a reoperation? Seriously? Well, I don’t see even a hint of a mechanism by which acupuncture might achieve this. Therefore, I would categorise this possibility as highly unlikely.
- It stands to reason that patients who are alive and well use more acupuncture than those who are dead or in need of surgery. So, this possibility is not entirely inconceivable.
- It seems very likely that people who are more health conscious might use acupuncture and live longer, need less readmissions or surgery. No doubt, this possibility is by far the best explanation of the findings of this retrospective matched cohort study.
If that is so, does this paper tell us anything useful at all?
Not really (that’s why it was published in an acupuncture journal which few people would read)
On second thought, perhaps it does tell us something valuable: retrospective matched cohort studies are hopeless when it comes to establishing cause and effect!
Yesterday, I received a tweet from a guy called Bart Huisman (“teacher beekeeping, nature, biology, classical homeopathy, agriculture, health science, social science”). I don’t know him and cannot remember whether I had previous contact with him. His tweet read as follows:
“Why should anyone believe what Professor Edzard Ernst says, after he put his name to a BBC programme, he now describes as “deception”.”
This refers to a story that I had almost forgotten. It’s a nice one with a ‘happy ending’, so let me recount it here briefly.
In 2005, the BBC had hired me as an advisor for their 4-part TV series on alternative medicine.
The first part of the series was on acupuncture, and Prof Kathy Sykes presented the opening scene taking place in a Chinese operation theatre. In it a Chinese women was having open heart surgery with the aid of acupuncture. Kathy’s was visibly impressed and said on camera that the patient was having the surgery “with only needles to control the pain.” However, the images clearly revealed that the patient was receiving all sorts of other treatments given through intra-venous lines. So, Prof Sykes was telling the UK public a bunch of porkies. This was bound to confuse many viewers.
One of them was Simon Singh. At the time, I did not know Simon (to be honest, I did not even know of him) and was surprised to receive a phone call from him. He politely asked me to confirm that I had been the adviser of the BBC on this production. I was happy to confirm this fact. Then he asked why I had missed such a grave error. I replied that I could not possibly have spotted it, because all I had been asked to do was to review and correct the text of the programme which the BBC had sent to me by email. Before it was broadcast, I had not seen a single passage of the film.
Correcting the text had already led to several problems (not so much regarding the acupuncture part but mostly the other sections), because the BBC was reluctant to change several of the mistakes I had identified. When I told them that, in this case, I would quit, they finally found a way to alter them. But the cooperation had been far from easy. I explained all this to Simon and eventually he asked me whether I would be willing to support the official complaint he was about to file with the BBC. I agreed. This is probably where I used the term ‘deception’ that Mr Huisman mentioned in his tweet.
So, Simon submitted his complaint and eventually won the case.
But this is not the happy ending I was referring to.
During the course of the complaint, Simon and I realised that we were thinking alike and were getting on well. A few months later, he suggested that the two of us write a book together about alternative medicine. At first, I was hesitant. Simon said, “let’s try just one chapter, and see how it works out.” So we did. It turned out to be fun and instructive for both of us. So we did the other chapters as well. The book was published in 2008 and is called TRICK OR TREATMENT. It was published in about 20 different languages and the German version became ‘science book of the year in 2011 (I think).
And that’s not the happy ending either (in fact, it caused a lot of hardship for Simon who was sued by the BCA; luckily, he won that case too).
The real happy ending is the fact that Simon and I became friends for life.
Thank you Bart Huisman for reminding me of this rather lovely story.
Cochrane reviews have the reputation to be the most reliable evidence available anywhere. They are supposed to be independent, rigorous, transparent and up-to-date. Usually, this reputation is justified, in my view. But do the 54 Cochrane reviews of acupuncture quoted in my previous post live up to it?
If one had to put the entire body of evidence in a nutshell, it would probably look something like this:
TOTAL NUMBER OF SYSTEMATIC REVIEWS = 54
POSITIVE CONCLUSIONS BASED ON MORE THAN ONE HIGH QUALITY STUDY = 2
FAILURE TO REACH CONVINCINGLY POSITIVE CONCLUSIONS = 52
The two positive reviews are on:
1) prevention of migraine
2) prevention of tension-type headache
Both of the positive reviews are by Linde et al.
Allow me to raise just a few further critical points:
- If I counted correctly, 19 of the 54 reviews are authored entirely by Chinese authors. Why could this be a problem? One reason could be that many Chinese authors seem to be biased in favour of acupuncture. Another reason could be that data fabrication is rife in China.
- Many if not most of the primary studies are published in Chinese. This means that it is impossible for most non-Chinese co-authors of the review as well as for the referees of the paper to check the accuracy of the data extraction.
- I counted a total of 15 reviews which were by authors who one could categorise as outspoken enthusiasts of acupuncture. In these cases, one might be concerned about the trustworthiness of the review’s conclusion.
- Many (some would say most) of the reviews cover subject areas which are frankly bizarre. Who would, for instance, consider acupuncture a plausible treatment for Glaucoma, Mumps or chronic hepatitis B?
- Despite almost all of the reviews demonstrating that there is no good reason to recommend acupuncture for the condition in question, hardly any of them draw a transparent, helpful and clear conclusion. One example might suffice: the review of acupuncture for hordeolum concluded that “Low‐certainty evidence suggests that acupuncture with or without conventional treatments may provide short‐term benefits for treating acute hordeolum…” Its Chinese authors reached this conclusion on the basis of 6 primary studies (all from China) which were all of lousy quality. In such a case, the only justified conclusion would be, in my view, something like this: THERE IS NO RELIABLE EVIDENCE …
Despite these serious limitations and avoidable confusions, the totality of the evidence from these 54 Cochrane reviews does send an important message: there is hardly a single condition for which acupuncture is clearly, convincingly and indisputably effective. What I find most regrettable, however, is that the Cochrane Collaboration allowed the often biased review authors to obscure this crucial message so thoroughly. One needs a healthy portion of critical thinking to get through to the truth here – and how many fans of acupuncture possess such a thing?
To update my article of 2008, I have searched the Cochrane Library for all Cochrane reviews specifically targeted at acupuncture or related interventions such as acupressure, electro-acupuncture and moxibustion (on 1/6/2020). More general reviews which included some evidence on acupuncture but were not specifically on this topic (e.g. complementary therapies for enuresis) were omitted.
It turned out that almost all the 32 reviews available in 2008 had been updated (some several times), a few had been abandoned and many new reviews have been added. In fact, the 32 reviews of 2008 have today grown into 54.
Here are the conclusions of and links to these papers:
- BELL’S PALSY The quality of the included trials was inadequate to allow any conclusion about the efficacy of acupuncture. More research with high quality trials is needed.
- PRIMARY DYSMENORRHOEA There is insufficient evidence to demonstrate whether or not acupuncture or acupressure are effective in treating primary dysmenorrhoea, and for most comparisons no data were available on adverse events. The quality of the evidence was low or very low for all comparisons. The main limitations were risk of bias, poor reporting, inconsistency and risk of publication bias.
- PREVENTION OF EPISODIC MIGRAINE The available evidence suggests that adding acupuncture to symptomatic treatment of attacks reduces the frequency of headaches. Contrary to the previous findings, the updated evidence also suggests that there is an effect over sham, but this effect is small. The available trials also suggest that acupuncture may be at least similarly effective as treatment with prophylactic drugs. Acupuncture can be considered a treatment option for patients willing to undergo this treatment. As for other migraine treatments, long‐term studies, more than one year in duration, are lacking.
- RHEUMATOID ARTHRITIS Although the results of the study on electroacupuncture show that electroacupuncture may be beneficial to reduce symptomatic knee pain in patients with RA 24 hours and 4 months post treatment, the reviewers concluded that the poor quality of the trial, including the small sample size preclude its recommendation. The reviewers further conclude that acupuncture has no effect on ESR, CRP, pain, patient’s global assessment, number of swollen joints, number of tender joints, general health, disease activity and reduction of analgesics. These conclusions are limited by methodological considerations such as the type of acupuncture (acupuncture vs electroacupuncture), the site of intervention, the low number of clinical trials and the small sample size of the included studies.
- PREVENTION OF TENSION TYPE HEADACHE: The available results suggest that acupuncture is effective for treating frequent episodic or chronic tension‐type headaches, but further trials ‐ particularly comparing acupuncture with other treatment options ‐ are needed.
- SHOULDER PAIN Due to a small number of clinical and methodologically diverse trials, little can be concluded from this review. There is little evidence to support or refute the use of acupuncture for shoulder pain although there may be short‐term benefit with respect to pain and function. There is a need for further well designed clinical trials.
- EPILEPSY Available RCTs are small, heterogeneous and have high risk of bias. The current evidence does not support acupuncture for treating epilepsy.
- CHRONIC ASTHMA There is not enough evidence to make recommendations about the value of acupuncture in asthma treatment. Further research needs to consider the complexities and different types of acupuncture.
- POLYCYSTIC OVARIAN SYNDROME For true acupuncture versus sham acupuncture we cannot exclude clinically relevant differences in live birth rate, multiple pregnancy rate, ovulation rate, clinical pregnancy rate or miscarriage. Number of intermenstrual days may improve in participants receiving true acupuncture compared to sham acupuncture. True acupuncture probably worsens adverse events compared to sham acupuncture. No studies reported data on live birth rate and multiple pregnancy rate for the other comparisons: physical exercise or no intervention, relaxation and clomiphene. Studies including Diane‐35 did not measure fertility outcomes as the women in these trials did not seek fertility.We are uncertain whether acupuncture improves ovulation rate (measured by ultrasound three months post treatment) compared to relaxation or Diane‐35. The other comparisons did not report on this outcome.Adverse events were recorded in the acupuncture group for the comparisons physical exercise or no intervention, clomiphene and Diane‐35. These included dizziness, nausea and subcutaneous haematoma. Evidence was very low quality with very wide CIs and very low event rates.There are only a limited number of RCTs in this area, limiting our ability to determine effectiveness of acupuncture for PCOS.
- CHRONIC HEPATITIS B The clinical effects of acupuncture for chronic hepatitis B remain unknown. The included trials lacked data on all‐cause mortality, health‐related quality of life, serious adverse events, hepatitis‐B related mortality, and hepatitis‐B related morbidity. The vast number of excluded trials lacked clear descriptions of their design and conduct. Whether acupuncture influences adverse events considered not to be serious is uncertain. It remains unclear if acupuncture affects HBeAg, and if it is associated with reduction in detectable HBV DNA. Based on available data from only one or two small trials on adverse events considered not to be serious and on the surrogate outcomes HBeAg and HBV DNA, the certainty of evidence is very low. In view of the wide usage of acupuncture, any conclusion that one might try to draw in the future should be based on data on patient and clinically relevant outcomes, assessed in large, high‐quality randomised sham‐controlled trials with homogeneous groups of participants and transparent funding.
- ENDOMETRIOSIS The evidence to support the effectiveness of acupuncture for pain in endometriosis is limited, based on the results of only a single study that was included in this review. This review highlights the necessity for developing future studies that are well‐designed, double‐blinded, randomised controlled trials that assess various types of acupuncture in comparison to conventional therapies.
- VASCULAR DEMENTIA The effectiveness of acupuncture for vascular dementia is uncertain. More evidence is required to show that vascular dementia can be treated effectively by acupuncture. There are no RCTs and high quality trials are few. Randomized double‐blind placebo‐controlled trials are urgently needed.
- FUNCTIONAL DYSPEPSIA It remains unknown whether manual acupuncture or electroacupuncture is more effective or safer than other treatments for patients with FD.
- SMOKING CESSATION Although pooled estimates suggest possible short‐term effects there is no consistent, bias‐free evidence that acupuncture, acupressure, or laser therapy have a sustained benefit on smoking cessation for six months or more. However, lack of evidence and methodological problems mean that no firm conclusions can be drawn. Electrostimulation is not effective for smoking cessation. Well‐designed research into acupuncture, acupressure and laser stimulation is justified since these are popular interventions and safe when correctly applied, though these interventions alone are likely to be less effective than evidence‐based interventions.
- RESTLESS LEG SYNDROME There is insufficient evidence to determine whether acupuncture is an efficacious and safe treatment for RLS. Further well‐designed, large‐scale clinical trials are needed.
- COCAINE DEPENDENCE There is currently no evidence that auricular acupuncture is effective for the treatment of cocaine dependence. The evidence is not of high quality and is inconclusive. Further randomised trials of auricular acupuncture may be justified.
- LABOUR PAIN Acupuncture in comparison to sham acupuncture may increase satisfaction with pain management and reduce use of pharmacological analgesia. Acupressure in comparison to a combined control and usual care may reduce pain intensity. However, for other comparisons of acupuncture and acupressure, we are uncertain about the effects on pain intensity and satisfaction with pain relief due to very low‐certainty evidence. Acupuncture may have little to no effect on the rates of caesarean or assisted vaginal birth. Acupressure probably reduces the need for caesarean section in comparison to a sham control. There is a need for further high‐quality research that include sham controls and comparisons to usual care and report on the outcomes of sense of control in labour, satisfaction with the childbirth experience or satisfaction with pain relief.
- ISCAEMIC ENCEPHALOPATHY The rationale for acupuncture in neonates with HIE is unclear and the evidence from randomized controlled trial is lacking. Therefore, we do not recommend acupuncture for the treatment of HIE in neonates. High quality randomized controlled trials on acupuncture for HIE in neonates are needed.
- LOW BACK PAIN The data do not allow firm conclusions about the effectiveness of acupuncture for acute low‐back pain. For chronic low‐back pain, acupuncture is more effective for pain relief and functional improvement than no treatment or sham treatment immediately after treatment and in the short‐term only. Acupuncture is not more effective than other conventional and “alternative” treatments. The data suggest that acupuncture and dry‐needling may be useful adjuncts to other therapies for chronic low‐back pain. Because most of the studies were of lower methodological quality, there certainly is a further need for higher quality trials in this area.
- AUTISM Current evidence does not support the use of acupuncture for treatment of ASD. There is no conclusive evidence that acupuncture is effective for treatment of ASD in children and no RCTs have been carried out with adults. Further high quality trials of larger size and longer follow‐up are needed.
- CARPAL TUNNEL SYNDROME Acupuncture and laser acupuncture may have little or no effect in the short term on symptoms of CTS in comparison with placebo or sham acupuncture. It is uncertain whether acupuncture and related interventions are more or less effective in relieving symptoms of CTS than corticosteroid nerve blocks, oral corticosteroids, vitamin B12, ibuprofen, splints, or when added to NSAIDs plus vitamins, as the certainty of any conclusions from the evidence is low or very low and most evidence is short term. The included studies covered diverse interventions, had diverse designs, limited ethnic diversity, and clinical heterogeneity. High‐quality randomised controlled trials (RCTs) are necessary to rigorously assess the effects of acupuncture and related interventions upon symptoms of CTS. Based on moderate to very‐low certainty evidence, acupuncture was associated with no serious adverse events, or reported discomfort, pain, local paraesthesia and temporary skin bruises, but not all studies provided adverse event data.
- ADHA A comprehensive search showed that there is no evidence base of randomised or quasi‐randomised controlled trials to support the use of acupuncture as a treatment for ADHD in children and adolescents. Due to the lack of trials, we cannot reach any conclusions about the efficacy and safety of acupuncture for ADHD in children and adolescents. This review highlights the need for further research in this area in the form of high quality, large scale, randomised controlled trials.
- FIBROMYALGIA There is low to moderate‐level evidence that compared with no treatment and standard therapy, acupuncture improves pain and stiffness in people with fibromyalgia. There is moderate‐level evidence that the effect of acupuncture does not differ from sham acupuncture in reducing pain or fatigue, or improving sleep or global well‐being. EA is probably better than MA for pain and stiffness reduction and improvement of global well‐being, sleep and fatigue. The effect lasts up to one month, but is not maintained at six months follow‐up. MA probably does not improve pain or physical functioning. Acupuncture appears safe. People with fibromyalgia may consider using EA alone or with exercise and medication. The small sample size, scarcity of studies for each comparison, lack of an ideal sham acupuncture weaken the level of evidence and its clinical implications. Larger studies are warranted.
- GLAUCOMA At this time, it is impossible to draw reliable conclusions from available data to support the use of acupuncture for treatment of patients with glaucoma. Because of ethical considerations, RCTs comparing acupuncture alone with standard glaucoma treatment or placebo are unlikely to be justified in countries where the standard of care has already been established.
- UTERINE FIBROIDS The effectiveness of acupuncture for the management of uterine fibroids remains uncertain. More evidence is required to establish the efficacy and safety of acupuncture for uterine fibroids. There is a continued need for well designed RCTs with long term follow up.
- HIP OSTEOARTHRITIS Acupuncture probably has little or no effect in reducing pain or improving function relative to sham acupuncture in people with hip osteoarthritis. Due to the small sample size in the studies, the confidence intervals include both the possibility of moderate benefits and the possibility of no effect of acupuncture. One unblinded trial found that acupuncture as an addition to routine primary physician care was associated with benefits on pain and function. However, these reported benefits are likely due at least partially to RCT participants’ greater expectations of benefit from acupuncture. Possible side effects associated with acupuncture treatment were minor.
- HYPERTENSION At present, there is no evidence for the sustained BP lowering effect of acupuncture that is required for the management of chronically elevated BP. The short‐term effects of acupuncture are uncertain due to the very low quality of evidence. The larger effect shown in non‐sham acupuncture controlled trials most likely reflects bias and is not a true effect. Future RCTs must use sham acupuncture controls and assess whether there is a BP lowering effect of acupuncture that lasts at least seven days.
- GASTROPARESISThere is very low‐certainty evidence for a short‐term benefit with acupuncture alone or acupuncture combined with gastrokinetic drugs compared with the drug alone, in terms of the proportion of people who experienced improvement in diabetic gastroparesis. There is evidence of publication bias and a positive bias of small study effects. The reported benefits should be interpreted with great caution because of the unclear overall risk of bias, unvalidated measurements of change in subjective symptoms, publication bias and small study reporting bias, and lack of data on long‐term outcomes; the effects reported in this review may therefore differ significantly from the true effect. One sham‐controlled trial provided low‐certainty evidence of no difference between real and sham acupuncture in terms of short‐term symptom improvement in diabetic gastroparesis, when measured by a validated scale. No studies reported changes in quality of life or the use of medication.Due to the absence of data, no conclusion can be made regarding effects of acupuncture on gastroparesis of other aetiologies. Reports of harm have remained largely incomplete, precluding assessments of the safety of acupuncture in this population. Future research should focus on reducing the sources of bias in the trial design as well as transparent reporting. Harms of interventions should be explicitly reported.
- ACUTE STROKE This updated review indicates that apparently improved outcomes with acupuncture in acute stroke are confounded by the risk of bias related to use of open controls. Adverse events related to acupuncture were reported to be minor and usually did not result in stopping treatment. Future studies are needed to confirm or refute any effects of acupuncture in acute stroke. Trials should clearly report the method of randomization, concealment of allocation, and whether blinding of participants, personnel, and outcome assessors was achieved, while paying close attention to the effects of acupuncture on long‐term functional outcomes.
- INSOMNIA Due to poor methodological quality, high levels of heterogeneity and publication bias, the current evidence is not sufficiently rigorous to support or refute acupuncture for treating insomnia. Larger high‐quality clinical trials are required.
- SCHIZOPHRENIA Limited evidence suggests that acupuncture may have some antipsychotic effects as measured on global and mental state with few adverse effects. Better designed large studies are needed to fully and fairly test the effects of acupuncture for people with schizophrenia.
- ACUTE HORDEOLUM Low‐certainty evidence suggests that acupuncture with or without conventional treatments may provide short‐term benefits for treating acute hordeolum when compared with conventional treatments alone. The certainty of the evidence was low to very low mainly due to small sample sizes, inadequate allocation concealment, lack of masking of the outcome assessors, inadequate or unclear randomization method, and a high or unreported number of dropouts. All RCTs were conducted in China, which may limit their generalizability to non‐Chinese populations.Because no RCTs included a valid sham acupuncture control, we cannot rule out a potential expectation/placebo effect associated with acupuncture. As resolution is based on clinical observation, the outcome could be influenced by the observer’s knowledge of the assigned treatment. Adverse effects of acupuncture were reported sparsely in the included RCTs, and, when reported, were rare. RCTs with better methodology, longer follow‐up, and which are conducted among other populations are warranted to provide more general evidence regarding the benefit of acupuncture to treat acute hordeolum.
- STROKE REHABILITATION From the available evidence, acupuncture may have beneficial effects on improving dependency, global neurological deficiency, and some specific neurological impairments for people with stroke in the convalescent stage, with no obvious serious adverse events. However, most included trials were of inadequate quality and size. There is, therefore, inadequate evidence to draw any conclusions about its routine use. Rigorously designed, randomised, multi‐centre, large sample trials of acupuncture for stroke are needed to further assess its effects.
- DEPRESSION The reduction in severity of depression was less when acupuncture was compared with control acupuncture than when acupuncture was compared with no treatment control, although in both cases, results were rated as providing low‐quality evidence. The reduction in severity of depression with acupuncture given alone or in conjunction with medication versus medication alone is uncertain owing to the very low quality of evidence. The effect of acupuncture compared with psychological therapy is unclear. The risk of adverse events with acupuncture is also unclear, as most trials did not report adverse events adequately. Few studies included follow‐up periods or assessed important outcomes such as quality of life. High‐quality randomised controlled trials are urgently needed to examine the clinical efficacy and acceptability of acupuncture, as well as its effectiveness, compared with acupuncture controls, medication, or psychological therapies.
- GAG REFLEX We found very low‐certainty evidence from four trials that was insufficient to conclude if there is any benefit of acupuncture, acupressure or laser at P6 point in reducing gagging and allowing successful completion of dental procedures. We did not find any evidence on any other interventions for managing the gag reflex during dental treatment. More well‐designed and well‐reported trials evaluating different interventions are needed.
- PERIPHERAL JOINT OSTEOARTHRITIS Sham‐controlled trials show statistically significant benefits; however, these benefits are small, do not meet our pre‐defined thresholds for clinical relevance, and are probably due at least partially to placebo effects from incomplete blinding. Waiting list‐controlled trials of acupuncture for peripheral joint osteoarthritis suggest statistically significant and clinically relevant benefits, much of which may be due to expectation or placebo effects.
- ELBOW PAIN There is insufficient evidence to either support or refute the use of acupuncture (either needle or laser) in the treatment of lateral elbow pain. This review has demonstrated needle acupuncture to be of short term benefit with respect to pain, but this finding is based on the results of 2 small trials, the results of which were not able to be combined in meta‐analysis. No benefit lasting more than 24 hours following treatment has been demonstrated. No trial assessed or commented on potential adverse effect. Further trials, utilising appropriate methods and adequate sample sizes, are needed before conclusions can be drawn regarding the effect of acupuncture on tennis elbow.
- MUMPS There is no evidence to determine the efficacy and safety of acupuncture in the treatment of children with mumps, although the excluded studies suggest that acupuncture is effective in improving swelling and pain of the parotid gland and assisting the body temperature to return to normal. We cannot make any recommendations for practice and nor can the results be generalised to clinical practice.
- MENOPAUSAL HOT FLUSHES 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.
- ASSISTED CONCEPTION There is no evidence that acupuncture improves live birth or pregnancy rates in assisted conception.
- HICCUPS A total of four studies (305 participants) met the inclusion criteria. All of these studies sought to determine the effectiveness of different acupuncture techniques in the treatment of persistent and intractable hiccups. All four studies had a high risk of bias, did not compare the intervention with placebo, and failed to report side effects or adverse events for either the treatment or control groups. Due to methodological differences we were unable to perform a meta‐analysis of the results. No studies investigating pharmacological interventions for persistent and intractable hiccups met the inclusion criteria.
- DYSPHAGIA IN ACUTE STROKE There is not enough evidence to make any conclusion about the therapeutic effect of acupuncture for dysphagia after acute stroke. High quality and large scale randomised controlled trials are needed.
- MOXIBUSTION FOR BREECH PRESENTATION This review found limited evidence to support the use of moxibustion for correcting breech presentation. There is some evidence to suggest that the use of moxibustion may reduce the need for oxytocin. When combined with acupuncture, moxibustion may result in fewer births by caesarean section; and when combined with postural management techniques may reduce the number of non‐cephalic presentations at birth, however, there is a need for well‐designed randomised controlled trials to evaluate moxibustion for breech presentation which report on clinically relevant outcomes as well as the safety of the intervention.
- CANCER PAIN There is insufficient evidence to judge whether acupuncture is effective in treating cancer pain in adults.
- URINARY INCONTINENCE The effect of acupuncture for stress urinary incontinence for adults is uncertain. There is not enough evidence to determine whether acupuncture is more effective than drug treatment.
- INDUCTION OF LABOUR Overall, there was no clear benefit from acupuncture or acupressure in reducing caesarean section rate. The quality of the evidence varied between low to high. Few trials reported on neonatal morbidity or maternal mortality outcomes. Acupuncture showed some benefit in improving cervical maturity, however, more well‐designed trials are needed. Future trials could include clinically relevant safety outcomes.
- NEUROPATHIC PAIN Due to the limited data available, there is insufficient evidence to support or refute the use of acupuncture for neuropathic pain in general, or for any specific neuropathic pain condition when compared with sham acupuncture or other active therapies. Five studies are still ongoing and seven studies are awaiting classification due to the unclear treatment duration, and the results of these studies may influence the current findings.
- PREMENSTRUAL SYNDROME The limited evidence available suggests that acupuncture and acupressure may improve both physical and psychological symptoms of PMS when compared to a sham control. There was insufficient evidence to determine whether there was a difference between the groups in rates of adverse events. There is no evidence comparing acupuncture or acupressure versus current ISPMD recommended treatments for PMS such as selective serotonin reuptake inhibitors (SSRIs). Further research is required, using validated outcome measures for PMS, adequate blinding and suitable comparator groups reflecting current best practice.
- IRRITABLE BOWEL SYNDROME Sham‐controlled RCTs have found no benefits of acupuncture relative to a credible sham acupuncture control for IBS symptom severity or IBS‐related quality of life. In comparative effectiveness Chinese trials, patients reported greater benefits from acupuncture than from two antispasmodic drugs (pinaverium bromide and trimebutine maleate), both of which have been shown to provide a modest benefit for IBS. Future trials may help clarify whether or not these reportedly greater benefits of acupuncture relative to pharmacological therapies are due entirely to patients’ preferences for acupuncture or greater expectations of improvement on acupuncture relative to drug therapy.
- ANKLE SPRAIN The currently available evidence from a very heterogeneous group of randomised and quasi‐randomised controlled trials evaluating the effects of acupuncture for the treatment of acute ankle sprains does not provide reliable support for either the effectiveness or safety of acupuncture treatments, alone or in combination with other non‐surgical interventions; or in comparison with other non‐surgical interventions. Future rigorous randomised clinical trials with larger sample sizes will be necessary to establish robust clinical evidence concerning the effectiveness and safety of acupuncture treatment for acute ankle sprains.
- MYOPAIA Two trials are included in this review but no conclusions can be drawn for the benefit of co‐acupressure for slowing progress of myopia in children. Further evidence in the form of RCTs are needed before any recommendations can be made for the use of acupuncture treatment in clinical use. These trials should compare acupuncture to placebo and have large sample sizes. Other types of acupuncture (such as auricular acupuncture) should be explored further as well as compliance with treatment for at least six months or longer. Axial length elongation of the eye should be investigated for at least one year. The potential to reduce/eliminate pain from acupuncture experienced by children should also be reviewed.
- CHRONIC KIDNEY DISEASE There was very low quality of evidence of the short‐term effects of manual acupressure as an adjuvant intervention for fatigue, depression, sleep disturbance and uraemic pruritus in patients undergoing regular haemodialysis. The paucity of evidence indicates that there is little evidence of the effects of other types of acupuncture for other outcomes, including pain, in patients with other stages of CKD. Overall high or unclear risk of bias distorts the validity of the reported benefit of acupuncture and makes the estimated effects uncertain. The incomplete reporting of acupuncture‐related harm does not permit us to assess the safety of acupuncture and related interventions. Future studies should investigate the effects and safety of acupuncture for pain and other common symptoms in patients with CKD and those undergoing dialysis.
- REHABILITATION OF BRAIN INJURY The low methodological quality of the included studies does not allow us to make conclusive judgments on the efficacy and safety of acupuncture in either the acute treatment and/or rehabilitation of TBI. Its beneficial role for these indications remains uncertain. Further research with high quality trials is required.
- POST-OPERATIVE NAUSEA AND VOMITING There is low‐quality evidence supporting the use of PC6 acupoint stimulation over sham. Compared to the last update in 2009, no further sham comparison trials are needed. We found that there is moderate‐quality evidence showing no difference between PC6 acupoint stimulation and antiemetic drugs to prevent PONV. Further PC6 acupoint stimulation versus antiemetic trials are futile in showing a significant difference, which is a new finding in this update. There is inconclusive evidence supporting the use of a combined strategy of PC6 acupoint stimulation and antiemetic drug over drug prophylaxis, and further high‐quality trials are needed.
The next and last part of this series will provide a few short comments on the current evidence.
Someone alerted me to a short article (2008) of mine that I had forgotten about. In it, I mention the 32 Cochrane reviews of acupuncture available at the time and the fact that they showed very little in favour of acupuncture. This made me wonder to what extent the situation might have changed in the last 12 years. So, I made a renewed attempt at evaluating this evidence. The entire exercise comes in three parts:
- My original paper from 2008
- The current evidence from Cochrane reviews
- Comments on the new evidence
Acupuncture has a long history of ups and downs. Its latest renaissance started in 1971, when a journalist in President Nixon’s press corps experienced symptomatic relief after being treated for postoperative abdominal distension. He reported this experience in The New York Times, which triggered a flurry of interest and research. In turn, it was discovered that needling might release endorphins in the brain or act via the gate control mechanism. Thus, plausible modes of action seemed to have been found, and the credibility of acupuncture increased significantly. Numerous clinical trials were initiated, and their results often suggested that acupuncture is clinically effective for a surprisingly wide range of conditions. Both a World Health Organization report and a National Institutes of Health consensus conference provided long lists of indications for which acupuncture allegedly was of proven benefit.
Many of the clinical studies, however, lacked scientific rigor. Most experts therefore remained unconvinced about the true value of acupuncture, particularly as a treatment for all ills. Some investigators began to suspect that the results were largely due to patient expectation. Others showed that the Chinese literature, a rich source of acupuncture trials, does not contain a single negative study of acupuncture, thus questioning the reliability of this body of evidence.
A major methodological challenge was the adequate control for placebo effects in clinical trials of acupuncture. Shallow needling or needling at non-acupuncture points had been used extensively for this purpose. Whenever the results of such trials did not show what acupuncture enthusiasts had hoped, they tended to claim that these types of placebos also generated significant therapeutic effects. Therefore, a negative result still would be consistent with acupuncture being effective. The development of non-penetrating needles was aimed at avoiding such problems. These “stage dagger”-like devices are physiologically inert and patients cannot tell them from real acupuncture. Thus, they fulfil the criteria for a reasonably good placebo.
The seemingly difficult question of whether acupuncture works had become complex—what type of acupuncture, for what condition, compared with no treatment, standard therapy, or to placebo, and what type of placebo? Meanwhile, hundreds of controlled clinical trials had become available, and their results were far from uniform. In this situation, systematic reviews might be helpful in establishing the truth, particularly Cochrane reviews, which tend to be more rigorous, transparent, independent, and up-to-date than other reviews. The traditional Chinese concept of acupuncture as a panacea is reflected in the fact that 32 Cochrane reviews are currently (January 2008) available, and a further 35 protocols have been registered. The notion of acupuncture as a “heal all” is not supported by the conclusions of these articles. After discarding reviews that are based on only 3 or fewer primary studies, only 2 evidence-based indications emerge: nausea/vomiting and headache. Even this evidence has to be interpreted with caution; recent trials using the above-mentioned “stage-dagger” devices as placebos suggest that acupuncture has no specific effects in either of these conditions.
Further support for the hypothesis that acupuncture is largely devoid of specific therapeutic effects comes from a series of 8 large randomized controlled trials (RCTs) initiated by German health insurers (Figure). These studies had a similar, 3-parallel-group design: pain patients were randomized to receive either real acupuncture, shallow needling as a placebo control, or no acupuncture. Even though not entirely uniform, the results of these studies tend to demonstrate no or only small differences in terms of analgesic effects between real and placebo acupuncture. Yet, considerable differences were observed between the groups receiving either type of acupuncture and the group that had no acupuncture at all.
The most recent, as-yet-unpublished trial also seems to confirm the “placebo hypothesis.” This National Institutes of Health-sponsored RCT included 640 patients with chronic back pain. They received either individualized acupuncture according to the principles of traditional Chinese medicine, or a standardized form of acupuncture, or sham acupuncture. The results demonstrate that acupuncture added to usual care was superior to usual care alone, individualized acupuncture was not more effective than standardized acupuncture, and neither type of real acupuncture was more effective than sham acupuncture.
Schematic representation of the recent acupuncture trials all following a similar 3-group design. These 8 randomized controlled trials related to chronic back pain, migraine, tension headache, and knee osteoarthritis (2 trials for each indication). Their total sample size was in excess of 5000. Patients in the “no acupuncture” group received either standard care or were put on a waiting list. Sham acupuncture consisted of shallow needling at non-acupuncture points. Real acupuncture was semi-standardized. The differences between the effects of both types of acupuncture and no acupuncture were highly significant in each study. The differences between sham and real acupuncture were, with the exception of osteoarthritis, not statistically significant.
Enthusiasts employ such findings to argue that, in a pragmatic sense, acupuncture is demonstrably useful: it is clearly better than no acupuncture at all. Even if it were merely a placebo, what really matters is to alleviate pain of suffering patients, never mind the mechanism of action. Others are not so sure and point out that all well-administrated treatments, even those that generate effects beyond placebo, will induce a placebo response. A treatment that generates only non-specific effects (for conditions that are amenable to specific treatments) cannot be categorized as truly effective or useful, they insist.
So, after 3 decades of intensive research, is the end of acupuncture nigh? Given its many supporters, acupuncture is bound to survive the current wave of negative evidence, as it has survived previous threats. What has changed, however, is that, for the first time in its long history, acupuncture has been submitted to rigorous science—and conclusively failed the test.
[references in the original paper]
Part 2 will be posted tomorrow.
The US ‘Agency for Healthcare Research and Quality (AHRQ) have published a most comprehensive review update entitled ‘Noninvasive Nonpharmacological Treatment for Chronic Pain‘. It followed the AHRQ Methods Guide for Effectiveness and Comparative Effectiveness. The conditions included were:
- Chronic low back pain
- Chronic neck pain
- Osteoarthritis (knee, hip, hand)
- Chronic tension headache
Here are the main findings related to acupuncture:
LOW BACK PAIN
- Acupuncture was associated with a small improvement in short-term function compared with sham acupuncture or usual care (4 trials); there was no difference between acupuncture and controls in intermediate-term (3 trials) or long-term (1 trial) function (SOE: low). Acupuncture was associated with small improvements in short-term (5 trials) and long-term (1 trial) pain compared with sham acupuncture, usual care, an attention control, or a placebo intervention but there was no difference in intermediate-term pain (5 trials) (SOE: moderate for short term, low for intermediate term and long term).
- Acupuncture was associated with small improvements in short-term (5 trials) and intermediate-term (3 trials) function versus sham acupuncture, a placebo (sham laser), or usual care; one trial reported no difference in function in the long term (SOE: low for all time periods). For pain, there were no differences for acupuncture versus sham acupuncture or placebo interventions in the short (4 trials), intermediate (3 trials), or long (1 trial) term (SOE: low for all time periods).
PAIN FROM KNEE OSTEOARTHRITIS
- No differences were seen between acupuncture and control interventions (sham acupuncture, waitlist, or usual care) for function in the short term (4 trials) or the intermediate term (4 trials) (SOE: low for short term; moderate for intermediate term). Stratified analysis showed no differences between acupuncture and sham treatments (4 trials) but moderate improvement in function compared with usual care (2 trials) short term. For pain, there were no differences between acupuncture versus control interventions in the short term (6 trials) or clinically meaningful differences in the intermediate term (4 trials) (SOE: low for short term; moderate for intermediate term). Short-term differences in pain were significant for acupuncture versus usual care but not for acupuncture versus sham acupuncture.
CHRONIC TENSION HEADACHE
- Laser acupuncture was associated with small, short-term improvements in pain intensity and in the number of headache days per month versus sham in one trial (SOE: low).
- Acupuncture was associated with a small improvement in function compared with sham acupuncture at short-term (3 trials [1 new]) and intermediate-term (2 trials) follow-up (SOE: moderate). There was no effect for acupuncture versus sham acupuncture on pain in the short term (4 trials [1 new]) or intermediate term (3 trials) (SOE: low) or based on pooled estimates across control conditions (sham or attention control, 5 trials [2 new]) SOE: low).
Treatment-related SAEs were rare (across 5 LBP, 5 neck pain, 4 FM, 1 knee OA, and 1 CTTH trial); only one event (needle insertion site pain lasting1 month) in a LBP patient (<1%) in one trial was considered related to treatment,
SAEs not considered to be related to acupuncture or the study conditions (range 0% to 9% across 5 LBP, 5 neck pain, 4 FM, 1 knee OA, and 1 CTTH trial). These included hospitalization (primarily) or outpatient treatment; reasons were not specified.
The most commonly reported non-serious AEs: swelling, bruising, bleeding or pain at the acupuncture site (1% to 61%, 12 RCTs; or 1% to 18% excluding an outlier trial)); numbness, discomfort, pain or increase in symptoms (1% to 14%; 11 RCTs), dizziness, nausea, fainting (1% to 7%, 7 RCTs), headache (1% to 2%; 4 RCTs), vasovagal symptoms (1% to 4%; 2 RCTs), respiratory problems, chest discomfort (1%; 2 neck pain RCTs), and infection at needle insertion site [1%; 1 RCT (knee OA)]
I find this interesting, especially if we consider that chronic pain is THE domain for acupuncture (as practised in the West). It shows that, contrary to what so many enthusiasts try to tell us, the evidence for acupuncture is very weak. It also demonstrates that, contrary to what some sceptics assume, the evidence is not totally negative.
As far as harms are concerned, we need to be aware of the fact that the above conclusions are based on clinical trials. We and others have repeatedly shown that in the real of SCAM many, if not most clinical studies fail to mention adverse effects. This means two things: firstly, the trialists violate research ethics; secondly, the above information is woefully incomplete.
Dry needling (DN), also known as myofascial trigger point dry needling, is a SCAM similar to acupuncture. It involves the use of solid filiform needles or hollow-core hypodermic needles and is usually employed for treating muscle pain. Instead of sticking them into acupuncture points, like with acupuncture, they are inserted into myofascial trigger points usually identified by palpation. There are some theories how DN might work, but whether it is clinically effective remains unclear.
This single-blind RCT determined, if the addition of upper quarter DN to a rehabilitation protocol is more effective in improving ROM, pain, and functional outcome scores when compared to a rehabilitation protocol alone after shoulder stabilization surgery. Thirty-nine post-operative shoulder patients were randomly allocated into two groups: (1) standard of care rehabilitation (control group) (2) standard of care rehabilitation plus dry needling (experimental group). Patient’s pain, ROM, and functional outcome scores were assessed at baseline (4 weeks post-operative), and at 8 weeks, 12 weeks, and 6 months post-operative.
Of 39 enrolled patients, 20 were allocated to the control group and 19 to the experimental group. At six-month follow up, there was a statistically significant improvement in shoulder flexion ROM in the control group. Aside from this, there were no significant differences in outcomes between the two treatment groups. Both groups showed improvement over time. No adverse events were reported.
The authors concluded that dry needling of the shoulder girdle in addition to standard of care rehabilitation after shoulder stabilization surgery did not significantly improve shoulder ROM, pain, or functional outcome scores when compared with standard of care rehabilitation alone. Both group’s improvement was largely equal over time. The significant difference in flexion at the six-month follow up may be explained by additional time spent receiving passive range of motion (PROM) in the control group. These results provide preliminary evidence that dry needling in a post-surgical population is safe and without significant risk of iatrogenic infection or other adverse events.
This trial followed the infamous A+B versus B design. As [A+B] is more than [B] alone, one would have expected that the experimental group has a better outcome than the control group.
But this was not the case!
Theoretically it can mean one of two things:
- DN did not even convey a placebo effect.
- DN had a negative effect on the outcome.