Asthma and the placebo effect

January 01, 0001

Asthma and the placebo effect

These US and UK investigators compared the effects of a bronchodilator, two placebo interventions, and no intervention on outcomes in patients with asthma. They conducted a double-blind, crossover pilot study in which they 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, they 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 (FEV1) was measured, and patients' self-reported improvement ratings were recorded.

They found: "Among the 39 patients who completed the study, albuterol resulted in a 20% increase in FEV1, as compared with approximately 7% with each of the other three interventions. 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%)."

The authors concluded: "Although albuterol, but not the two placebo interventions, improved FEV1 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."

Patients think that they improve with placebo treatments, but FEV1 does not improve.

For the full abstract, click here.

N Engl J Med 365:119-126, 14 July 2011 © 2011 to the Massachusetts Medical Society
Active Albuterol or Placebo, Sham Acupuncture, or No Intervention in Asthma. Michael E. Wechsler, John M. Kelley, Ingrid O.E. Boyd, et al. Correspondence to Dr. Weschler: [email protected]

Category: R. Respiratory. Keywords: albuterol, placebo, sham acupuncture, randomized controlled trial, journal watch.
Synopsis edited by Dr Linda French, Toledo, Ohio. Posted on Global Family Doctor 2 August 2011

Pearls are an independent product of the Cochrane primary care group and are meant for educational use and not to guide clinical care.