Acupuncture for treatment of irritable bowel syndrome: Cochrane systematic review
Assessed as up to date: 2011/11/15
Irritable bowel syndrome (IBS) is a common, costly, and difficult to treat disorder that impairs health-related quality of life and work productivity. Evidence-based treatment guidelines have been unable to provide guidance on the effects of acupuncture for IBS because the only previous systematic review included only small, heterogeneous and methodologically unsound trials.Objectives
The primary objectives were to assess the efficacy and safety of acupuncture for treating IBS.Search methods
MEDLINE, the Cochrane Central Register of Controlled Trials, EMBASE, the Cumulative Index to Nursing and Allied Health, and the Chinese databases Sino-Med, CNKI, and VIP were searched through November 2011.Selection criteria
Randomized controlled trials (RCTs) that compared acupuncture with sham acupuncture, other active treatments, or no (specific) treatment, and RCTs that evaluated acupuncture as an adjuvant to another treatment, in adults with IBS were included.Data collection and analysis
Two authors independently assessed the risk of bias and extracted data. We extracted data for the outcomes overall IBS symptom severity and health-related quality of life. For dichotomous data (e.g. the IBS Adequate Relief Question), we calculated a pooled relative risk (RR) and 95% confidence interval (CI) for substantial improvement in symptom severity after treatment. For continuous data (e.g. the IBS Severity Scoring System), we calculated the standardized mean difference (SMD) and 95% CI in post-treatment scores between groups.Main results
Seventeen RCTs (1806 participants) were included. Five RCTs compared acupuncture versus sham acupuncture. The risk of bias in these studies was low. We found no evidence of an improvement with acupuncture relative to sham (placebo) acupuncture for symptom severity (SMD -0.11, 95% CI -0.35 to 0.13; 4 RCTs; 281 patients) or quality of life (SMD = -0.03, 95% CI -0.27 to 0.22; 3 RCTs; 253 patients). Sensitivity analyses based on study quality did not change the results. A GRADE analysis indicated that the overall quality of the evidence for the primary outcomes in the sham controlled trials was moderate due to sparse data. The risk of bias in the four Chinese language comparative effectiveness trials that compared acupuncture with drug treatment was high due to lack of blinding. The risk of bias in the other studies that did not use a sham control was high due to lack of blinding or inadequate methods used for randomization and allocation concealment or both. Acupuncture was significantly more effective than pharmacological therapy and no specific treatment. Eighty-four per cent of patients in the acupuncture group had improvement in symptom severity compared to 63% of patients in the pharmacological treatment group (RR 1.28, 95% CI 1.12 to 1.45; 5 studies, 449 patients). A GRADE analysis indicated that the overall quality of the evidence for this outcome was low due to a high risk of bias (no blinding) and sparse data. Sixty-three per cent of patients in the acupuncture group had improvement in symptom severity compared to 34% of patients in the no specific therapy group (RR 2.11, 95% CI 1.18 to 3.79; 2 studies, 181 patients). There was no statistically significant difference between acupuncture and Bifidobacterium (RR 1.07, 95% CI 0.90 to 1.27; 2 studies; 181 patients) or between acupuncture and psychotherapy (RR 1.05, 95% CI 0.87 to 1.26; 1 study; 100 patients). Acupuncture as an adjuvant to another Chinese medicine treatment was significantly better than the other treatment alone. Ninety-three per cent of patients in the adjuvant acupuncture group improved compared to 79% of patients who received Chinese medicine alone (RR 1.17, 95% CI 1.02 to 1.33; 4 studies; 466 patients). There was one adverse event (i.e. acupuncture syncope) associated with acupuncture in the 9 trials that reported this outcome, although relatively small sample sizes limit the usefulness of these safety data.Authors' conclusions
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.
Manheimer Eric, Cheng Ke, Wieland L. Susan, Min Li Shih, Shen Xueyong, Berman Brian M, Lao Lixing
Acupuncture for irritable bowel syndrome
Irritable bowel syndrome (IBS) is a chronic gastrointestinal condition characterized by altered bowel habits and abdominal pain and discomfort. It is a common, costly, and difficult to treat disorder that also impairs health-related quality of life and work productivity. Some pharmacological (i.e. drug) therapies for treating IBS have modest benefits and a risk for side effects, and therefore, it is important to evaluate the effectiveness and safety of non-drug therapies, including acupuncture. One problem with trials in IBS is that placebo effects are often seen in IBS treatment. Placebo effects are improvements in symptoms that are due to patient beliefs in a particular treatment rather than the specific biological effects of the treatment.
This review included 17 randomized controlled trials (RCTs) including a total of 1806 participants. Five RCTs (411 participants) compared acupuncture to sham acupuncture for the treatment of IBS. Sham acupuncture is a procedure in which the patient believes he or she is receiving true acupuncture. However, in sham acupuncture the needles either do not penetrate the skin or are not placed at the correct places on the body, or both. Sham acupuncture is intended to be a placebo for true acupuncture. The sham-controlled studies were well designed and of high methodological quality. These studies tested the effects of acupuncture on IBS symptom severity or health-related quality of life. None of these RCTs found acupuncture to be better than sham acupuncture for either of these two outcomes, and pooling the results of these RCTs also did not show acupuncture to be better than sham acupuncture. Evidence from four Chinese language comparative effectiveness trials showed acupuncture to be superior to two antispasmodic drugs (pinaverium bromide and trimebutine maleate), both of which provide a modest benefit for the treatment of IBS, although neither is approved for treatment of IBS in the United States. It is unclear whether or not the greater benefits of acupuncture reported by patients in these unblinded studies are due entirely to patients’ greater expectations of improvement from acupuncture than drugs or preference for acupuncture over drug therapy. There was one side effect (i.e. fainting in one patient) associated with acupuncture in the nine trials that reported side effects, although relatively small sample sizes limit the usefulness of this safety data.
Implications for practice
People with IBS have few treatment options available. Pharmacological therapies provide modest benefits (Ford 2009a), can have high costs, and some of the newer drugs have been withdrawn from the market because of adverse events (Thompson 2001; Pasricha 2007). Safe, non-pharmacological therapies that may allow patients to feel more empowered and more in control of their symptoms should be evaluated for effectiveness. However, evaluating complex non-pharmacological therapies for IBS (e.g. mindfulness meditation (Gaylord 2011) or hypnotherapy (Lindfors 2012)) poses challenges, particularly in regards to selecting a placebo control or a credible alternative treatment control.
While acupuncture can theoretically be compared with a sham acupuncture “placebo” control, a fundamental challenge has been developing a sham acupuncture control that is sufficiently believable to patients so as to be indistinguishable from true acupuncture, and yet at the same time not so similar to true acupuncture that the sham has a therapeutic effect of its own and is therefore not an inert placebo. The sham acupuncture controls used in four of the five sham-controlled trials in this review appeared to be believable as authentic treatments (Forbes 2005; Schneider 2006; Lembo 2009; Anastasi 2009), but two of the five sham-controlled trials used sham controls that might have had weak physiological activity (Forbes 2005; Anastasi 2009), and therefore these shams may not have been completely inert placebos. While none of the sham-controlled trials showed a benefit of acupuncture relative to sham acupuncture, it is still not clear whether these findings are because acupuncture has no true biological effect above and beyond a placebo; or whether instead acupuncture has small biological effects, but the small sample sizes and heterogeneity of participants and interventions in these trials precluded detecting a statistically significant pooled benefit of acupuncture over sham; or whether any biological effects of true acupuncture cannot be detected because they are overridden and obscured by the large placebo effects of the sham control (Kaptchuk 2006; Wechsler 2011). Evidence from four Chinese language comparative effectiveness trials (Shi 2010; Zeng 2010; Chen 2011; Sun 2011) showed acupuncture to be superior to two antispasmodic drugs (pinaverium bromide and trimebutine maleate), both of which have consistently been shown to provide a modest benefit in high quality trials (Jailwala 2000; Ruepert 2011), although neither is approved for treatment of IBS in the United States (Jailwala 2000). Patient preferences and expectations may partly explain the positive findings of these trials comparing acupuncture to drug treatment. That is, if the trial participants had pretreatment preferences for acupuncture over drugs, these preferences may have influenced the participants’ later assessments of their subjective states, as reported on the patient-reported outcome measures used (Kalauokalani 2001; Linde 2007; Manheimer 2007; O'Connell 2009).
In addition to efficacy, safety and costs are other considerations. Safety is best determined with large prospective surveys of practitioners and three such surveys (MacPherson 2001; White 2001; Melchart 2004) show that serious adverse events after acupuncture are rare. There was one adverse event associated with acupuncture in the nine trials that reported this outcome (Forbes 2005; Reynolds 2008; Anastasi 2009; Chen 2009; Lembo 2009; An 2010; Liu 2010; Shi 2010; Sun 2011), although relatively small sample sizes limit the usefulness of these safety data. Finally, patients would also need to consider costs because acupuncture treatment often needs to be paid for out of pocket.
Implications for research
Considering that our meta-analysis found no differences between acupuncture and sham, and also considering that there are limited resources available to conduct trials of acupuncture, a non-proprietary therapy, additional sham-controlled trials of acupuncture among IBS patients should not be a high priority in acupuncture research, at least until the large, ongoing sham-controlled trial, which is expected to complete data collection in March 2013, is published (Anastasi). This trial (n = 171) (Anastasi) compares a sham control with two different acupuncture test treatment groups, one test group using a fixed formula and the other test group using an individualized treatment approach, for patients with diarrhea-predominant IBS (See Characteristics of ongoing studies). If this trial shows no benefit of acupuncture relative to the sham, then the need for additional sham-controlled trials would seem questionable. However, if this ongoing sham-controlled trial shows a benefit, then it would certainly be warranted to conduct future sham-controlled trials building upon the results of this trial (e.g. restriction to diarrhea predominant IBS patients; using the same acupoints as used in this trial). Such future sham-controlled trials should use non-penetrating, but demonstrably credible, shams to control for placebo effects, and ideally these sham needles should be placed far away from the true acupuncture points.
Because of the difficulties of controlling for placebo effects in acupuncture for IBS trials, which typically evaluate strictly subjective, patient-reported outcomes (e.g. symptom severity, quality of life), another approach forward for research is the evaluation of objective or semi-objective outcomes in IBS patients, using pragmatic and cost-effectiveness trials. Indeed, a recently completed trial (n = 220) (Principal Investigator: MacPherson) compared the effectiveness and cost-effectiveness of acupuncture plus usual general practitioner (GP) care versus usual GP care alone, on the semi-objective outcomes of medication use, health service use, and days lost from work (MacPherson 2010). Although this trial does not include a placebo control, because the outcome measures being assessed in this trial are semi-objective, its results will be less influenced by expectation effects (Wood 2008; Hrobjartsson 2010; Manheimer 2011), than trials that assess only strictly subjective outcomes (i.e., patient reports of symptom improvement). Indeed, the Rome criteria for design of IBS treatment trials note that placebo effects “are especially a problem where end points are subjective” (Irvine 2006). If this recently completed cost-effectiveness trial shows that acupuncture reduces healthcare utilization, then whether the resulting cost-savings are due to a specific effect of acupuncture needling or non-specific effects (e.g. greater autonomy and empowerment of patients, positive patient-practitioner relationship) seems of secondary importance. However, it must be borne in mind that the patient population who elected to participate in this acupuncture trial may have stronger a priori beliefs about the benefits of acupuncture, than does the average population of IBS patients, and therefore, the non-specific effects experienced by the patients in this unblinded trial may not be generalizable to the results that would be obtained among an average population of IBS patients. However, the results of this trial may be generalizable to the subset of IBS patients in general practice who would elect to receive acupuncture because such patients may also have a priori expectations for acupuncture to be beneficial. To produce results generalizable to the average population of IBS patients, investigators of future pragmatic trials might minimize the recruitment of participants with an a priori preference for acupuncture by not specifying, in the recruitment of patients, that acupuncture is one of the treatment options being investigated.
Future comparative effectiveness trials would also be helpful to validate and extend the preliminary evidence in this review, which suggests that acupuncture is associated with greater improvements in subjective patient self-assessments than pharmacological therapies. As previously mentioned, a limitation of the acupuncture versus pharmacological therapy trials in this review is that they did not use a design that controlled for the effects of patients’ expectations for improvement, patient preferences, and non-specific therapeutic factors. Indeed, in the Chinese trials included in this review, the patients may well have had pre-treatment preferences for acupuncture, considering that these trials were conducted at hospitals of traditional Chinese medicine. Because acupuncture may elicit a greater expectation effect than pharmacological therapies or other active treatments (Kaptchuk 2006; Manheimer 2007; O'Connell 2009), particularly among participants who have a preference for acupuncture, investigators conducting future trials that compare acupuncture with other active therapies should consider asking participants about their preferences and expectations (before and after the intervention), and studying the potential effects of pre-treatment preferences on study outcomes. Such trials should also include a credibility questionnaire to establish that the treatments being compared are perceived by the patients as equally credible treatments for IBS symptoms (Gaylord 2011). Future comparative effectiveness trials in the West should also consider using a daily frequency of acupuncture, as was used in the Chinese trials in this review. However, even with additional well-designed trials, the truth about the effects of acupuncture for IBS will likely always be difficult to assess because the complexities and potential biases inherent to both the comparative effectiveness and sham acupuncture control designs makes it difficult to evaluate the subjective, patient-reported outcomes typically used in IBS trials.Get full text at The Cochrane Library
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