A meta‐analysis of the placebo response in complementary and alternative medicine trials of irritable bowel syndrome

Abstract

Among patients with irritable bowel syndrome (IBS) enrolled in clinical trials of conventional medical therapy, the placebo response rate is high. IBS patients also frequently use complementary and alternative medicine (CAM), which may act through an 'enhanced placebo effect'. The purpose of this study was to estimate the magnitude of the placebo response rate in CAM trials for IBS and to identify factors that influence this response. We performed a systematic review and meta-analysis of randomized, placebo-controlled clinical trials of CAM therapies for IBS identified from MEDLINE/EMBASE/PsychLIT databases from 1970 to 2006. Placebo and active treatment response rates for global symptom improvement were assessed. Nineteen studies met the inclusion criteria. The pooled estimate of the placebo response rate was 42.6% (95% confidence interval, 38.0-46.5%). Significant heterogeneity existed across trials (range 15.0-72.2%, P < 0.00001). Higher placebo response rates correlated with a longer duration of treatment (r = 0.455, P = 0.05) and a greater number of office visits (r = 0.633, P = 0.03). Among IBS patients in CAM trials, the placebo response rate is high. That this rate is similar in magnitude to that seen in conventional medicine trials suggests that the placebo response is independent of the type of therapy used and that it is not particularly 'enhanced' in CAM trials.

Probiotics in irritable bowel syndrome: underachievers or underpowered? authors’ reply

“…3 We agree with the complexity and the clinical relevance of this topic. Despite the evidence that most lactose malabsorbers can tolerate lactose amounts below 12 g, 4 gastrointestinal symptoms are also reported after ingestion of smaller doses of lactose.…”

The Placebo Response Rate in Irritable Bowel Syndrome and Inflammatory Bowel Disease

“…Dorn et al [10] performed a meta-analysis of placebo response in complementary and alternative medicine (CAM) trials in IBS. The authors performed a systematic review and meta-analysis of randomized placebo-controlled trials of CAM therapies for IBS performed between 1970 and 2006.…”

A Possible Mechanism of Action for the Placebo Response: Human Biofield Activation Via Therapeutic Ritual

“…Different types of therapeutic rituals activate the placebo or meaning making response in patients to varying degrees. Sometimes therapeutic rituals used in conventional and alternative treatment approaches elicit the same levels of placebo response, as found by a meta-analysis of CAM treatments for irritable bowel syndrome (Dorn et al, 2007); sometimes therapeutic rituals used in CAM approaches appear more effective than those used in conventional treatments, as found in the previously mentioned study on lower back pain (Cherkin et al, 2009); and sometimes the conventional approach yields higher placebo response rates than CAM approaches, as in Freeman et al's (2010) meta-analysis of CAM and conventional treatments for depression. The observed healing benefits of traditional medical systems such as indigenous healing practices, Ayurvedic medicine from India, Traditional Chinese Medicine, and naturopathy, have often been attributed entirely to therapeutic ritual healing (Kwan, 2007;Wampold et al, 2005), as have the observed benefits of energy-medicine techniques such as Reiki, qigong, and Therapeutic Touch (Ernst, 2006;Jonas & Chez, 2003;Martin & Henderson, 2011;Rein, 2004).…”