A closer look at the placebo effect

Posted 20 July 2011

From Medical Xpress

Published:   July 13th, 2011 in Medications

Placebos are "dummy pills" often used in research trials to test new  drug therapies and the "placebo effect" is the benefit patients  receive from a treatment that has no active ingredients. Many claim  that the placebo effect is a critical component of clinical practice. 

But whether or not placebos can actually influence objective measures  of disease has been unclear. Now a study of asthma patients examining  the impact of two different placebo treatments versus standard medical  treatment with an albuterol bronchodilator has reached two important conclusions: while placebos had no effect on lung function (one of the  key objective measures that physicians depend on in treating asthma patients) when it came to patient-reported outcomes, placebos were  equally as effective as albuterol in helping to relieve patients' discomfort and their self-described asthma symptoms.

The study was led by Harvard Medical School investigators at Brigham  and Women's Hospital (BWH) and Beth Israel Deaconess Medical Center (BIDMC) and appears in the July 14 issue of The New England Journal of  Medicine (NEJM).

"We were trying to understand whether a placebo effect exists and, if  so, whether it was similar with regard to both objectively and  subjectively reported measures, and whether similar effects could be  observed using different types of placebo," explains lead author  Michael Wechsler, MD, Associate Director of the Asthma Research Center  at BWH and Assistant Professor of Medicine at Harvard Medical School  (HMS).

The study examined 39 patients with chronic asthma who were randomly  assigned to undergo treatment with an active albuterol inhaler, with a  placebo albuterol inhaler, with sham acupuncture, or with no  intervention at all. The researchers administered one of each of the  three treatment interventions to each of the study participants, plus  a no intervention session, in random order during sequential medical  visits (three to seven days apart from each other). The procedures  were repeated in two more blocks of visits, such that each patient had  a total of 12 medical visits.

At the study's conclusion, findings showed that treatment with the  albuterol inhaler resulted in a 20 percent increase in FEV1 (maximum  forced expiratory volume in one second ), a measure of lung capacity.

This compared with an increase of approximately seven percent in each  of the two placebo treatments as well as the "no treatment" control.

"Since there was no difference between either of the placebo  treatments and the placebo 'control' [no treatment], we can report  that there was no objective placebo effect with regard to change in  lung function," says Wechsler.

However, patients' descriptions of their symptoms suggested that a  subjective placebo effect does exist: patients reported statistically  significant symptomatic improvement with albuterol, as well as with  the placebo inhaler and with sham acupuncture. This compared to little  improvement, if any, when patients received no treatment at all.

"We chose to study patients with asthma because earlier evidence had  suggested that placebos would change the underlying medical problem," explains senior author Ted Kaptchuk, Director of the Program in  Placebo Studies at BIDMC and Associate Professor of Medicine at HMS.

"While I was initially surprised that there was no placebo effect in  this experiment [after looking at the objective air flow measures]  once I saw patients' subjective descriptions of how they felt  following both the active treatment and the placebo treatments, it was  apparent that the placebos were as effective as the active drug in  helping people feel better." 

These findings, says Wechsler, suggest that physicians and  investigators reconsider the implications of subjective, patient-  reported outcomes in clinical trials, and consider having a "placebo  for the placebo" to monitor a patient's natural history. 

"Despite beneficial effects on objective physiological outcome,  pharmacologic therapy may not provide incremental benefit on  subjective symptoms provided by placebos," Wechsler adds. "But while  placebos remain an essential component of clinical trials to validate  objective findings, assessment of natural history is essential in the  final assessment of patient-reported outcomes." 

At the same time, adds Kaptchuk, the study results imply that placebo  treatment is just as effective as active medication in improving  patient-centered outcomes. 

"It's clear that for the patient, the ritual of treatment can be very  powerful," notes Kaptchuk. "This study suggests that in addition to  active therapies for fixing diseases, the idea of receiving care is a  critical component of what patients value in health care. In a climate  of patient dissatisfaction, this may be an important lesson." 

Provided by Beth Israel Deaconess Medical Center 

 

Postscript

Kevin has posted a link below, a link to an article that deconstructs the published original article this post refers to, and in the process raises a number of very valid points – but more than that, demonstrates how one should carefully assess data for one's self.

One Response to A closer look at the placebo effect

  1. Kevin 20 July, 2011 at 1:52 pm #

    Thanks Harris.  I noticed a good comment on this study by Orac over at Respectful Insolence http://scienceblogs.com/insolence/2011/07/dangerous_placebo_medicine_in_asthma.php

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.