Study (2011, on Asthma) showing placebos changed subjective outcome measure but not objective one

[Dolphin]

I think it was somebody on PR who recommendeded this. I've just read it and thought it was good.

Free full text: http://www.nejm.org/doi/full/10.1056/NEJMoa1103319

Active albuterol or placebo, sham acupuncture, or no intervention in asthma.

N Engl J Med. 2011 Jul 14;365(2):119-26. doi: 10.1056/NEJMoa1103319

Wechsler ME1, Kelley JM, Boyd IO, Dutile S, Marigowda G, Kirsch I, Israel E, Kaptchuk TJ.


Abstract

BACKGROUND:

In prospective experimental studies in patients with asthma, it is difficult to determine whether responses to placebo differ from the natural course of physiological changes that occur without any intervention.

We compared the effects of a bronchodilator, two placebo interventions, and no intervention on outcomes in patients with asthma.

METHODS:

In a double-blind, crossover pilot study, we randomly assigned 46 patients with asthma to active treatment with an albuterol inhaler, a placebo inhaler, sham acupuncture, or no intervention.

Using a block design, we administered one each of these four interventions in random order during four sequential visits (3 to 7 days apart); this procedure was repeated in two more blocks of visits (for a total of 12 visits by each patient).

At each visit, spirometry was performed repeatedly over a period of 2 hours. Maximum forced expiratory volume in 1 second (FEV(1)) was measured, and patients' self-reported improvement ratings were recorded.

RESULTS:

Among the 39 patients who completed the study, albuterol resulted in a 20% increase in FEV(1), as compared with approximately 7% with each of the other three interventions (P<0.001).

However, patients' reports of improvement after the intervention did not differ significantly for the albuterol inhaler (50% improvement), placebo inhaler (45%), or sham acupuncture (46%), but the subjective improvement with all three of these interventions was significantly greater than that with the no-intervention control (21%) (P<0.001).

CONCLUSIONS:

Although albuterol, but not the two placebo interventions, improved FEV(1) in these patients with asthma, albuterol provided no incremental benefit with respect to the self-reported outcomes.

Placebo effects can be clinically meaningful and can rival the effects of active medication in patients with asthma.

However, from a clinical-management and research-design perspective, patient self-reports can be unreliable.

An assessment of untreated responses in asthma may be essential in evaluating patient-reported outcomes.
(Funded by the National Center for Complementary and Alternative Medicine.).

 

[alex3619]

So a placebo treatment alters attitude toward patient health, but not the health.

This article can directly be cited as an example of why the PACE trial claims may be wrong.

I will need to read the paper though. I wonder what to make of this line:

Placebo effects can be clinically meaningful and can rival the effects of active medication in patients with asthma.

 

[barbc56]

@Dolphin

I have been looking for this very study as I wanted to bookmark it. I did mention in a post I was looking for it but don't remember in what context or how long ago this was, so I'm not sure if this is where you saw it mentioned.

This study has so many implications.

Thanks!

Barb

 

[eafw]

I will need to read the paper though. I wonder what to make of this line:

"Placebo effects can be clinically meaningful and can rival the effects of active medication in patients with asthma".

That line is from the abstract, and slightly ambiguous as it stands alone there. It makes more sense in the context of what they say in the paper itself

"Our research has important implications both for the treatment of asthma and for clinical-trial design in general. Many patients with asthma have symptoms that remain uncontrolled, and the discrepancy between objective pulmonary function and patients' self-reports noted in this study suggests that subjective improvement in asthma should be interpreted with caution and that objective outcomes should be more heavily relied on for optimal asthma care. Indeed, although improvement in objective measures of lung function would be expected to correlate with subjective measures, our study suggests that in clinical trials, reliance solely on subjective outcomes may be inherently unreliable, since they may be significantly influenced by placebo effects."

IOW, placebo is clinically meaningful in terms of reported effects, to the extent it can give a reported improvement as good as the active drug. But reported effects are unreliable - they don't correlate to actual effects - so should be used with caution when claiming a particular outcome.