In the trial of 80 irritable bowel syndrome (IBS) patients, those who took an open-label placebo showed clinically meaningful -- and statistically significantly -- higher global improvement scores and reduced symptom severity compared with those who got the same physician attention but didn't pop a placebo pill, Ted J. Kaptchuk, OMD (Doctor of Oriental Medicine), of the Beth Israel Deaconess Medical Center and Harvard, and colleagues found.
Surprisingly, the 59% rate of "adequate relief" with the known placebo was substantially greater than the typical 30% to 40% placebo response in double-blind IBS trials and actually comparable to responder rates seen with drugs used for IBS, they reported in the December issue of PLoS One.
While this may seem counterintuitive, the results suggest that physicians don't have to resort to deception to harness the power of the placebo effect, Kaptchuk explained in an interview.
"Conventional wisdom says that in order for a placebo to work you have to convince the patient that they are taking a real drug," he told MedPage Today.
However, the brain appears to respond to placebo in a way that conditions like IBS are susceptible to, Kaptchuk noted.
"We presume that the mechanisms in this study are probably analogous to the mechanisms in concealed placebo studies where we know that placebo treatment activates endogenous opioids or dopamine and can activate specific areas of the brain that modulate pain," he said in the interview.
This effect may have its greatest potential in conditions that are defined by patient complaints and have shown large placebo effects in blinded trials, such as chronic pain, fibromyalgia, and possibly depression and anxiety, he suggested.
"We're not questioning that people have real symptoms and real suffering in illnesses that are defined by self report," he told MedPage Today. "We're saying these kind of illness are more susceptible to modulation of symbol and mind-body effects."
A survey of physicians suggested that about half of them already use sham interventions to harness the placebo effect in their practice.These current study opens up the possibility of doing so without resorting to deception, Kaptchuk noted -- while warning that his group's finding is just a proof-of-concept study that should be treated cautiously.
The trial included 80 primarily female (70%) patients with IBS randomized to no treatment or an open-label placebo presented as "placebo pills made of an inert substance, like sugar pills, that have been shown in clinical studies to produce significant improvement in IBS symptoms through mind-body self-healing processes."
Although both groups got the same quality of interaction with their providers to control for the role of the doctor-patient relationship, the placebo group came in significantly higher on the primary outcome measure of IBS Global Improvement Scale score after three weeks of treatment.
Global improvement scores averaged 5.0 versus 3.9 with no treatment (P=0.002), which at the large effect size of 0.79 was clinically meaningful, according to the researchers.
Placebo also reduced symptom severity by 92 points on the IBS Symptom Severity Scale, which was not only 46 points more than with no treatment (P=0.03) but also well above the 50-point threshold for a meaningful improvement from baseline on that scale.
Quality of life showed a trend (P=0.08) for greater improvement with placebo at the end of the trial as well with an 11-point boost over baseline. An increase of 10 points is considered clinically meaningful on the scale used.
"There's a specific effect to the ritual of medicine that, in fact, the caring a doctor gives, the treatments they give irregardless of what's in them is an important component of healthcare and is an potential optional therapy in healthcare," Kaptchuk concluded in the interview.
However, his group cautioned that further study and replication are needed before use of open-label placebo in practice.
Limitations of the trial included a relatively small sample size, too short duration to examine long-term effects, and the possibility of self-selection bias in that the trial may have selectively attracted IBS patients interested in mind-body interventions.
Additionally, the study was restricted to a group of patients with a single diagnosis, which may affect is generalizability.
http://www.medpagetoday.com/PainManagement/PainManagement/24056
