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Tuesday, November 19, 2013

Claritin advertisements cause a placebo effect

It is well known that beliefs about the quality of a drug can enhance its physiological effect, but little is known of the impact of advertising of a branded drug. Kamenica et al (PNAS August 2013) conducted a clinical trial to measure the physiological impact of direct-to-consumer advertising of the antihistamine Claritin. The authors exposed subjects with or without allergies to a skin test of common allergens, and then subjects received Claritin, and viewed advertisements for Claritin or Zyrtec.  Regardless of allergy, all subjects experienced a wheal reaction to the skin test. In the allergy subpopulation, there was no significant change in beliefs associated with exposure to Claritin advertisements; however, in the subpopulation without allergies, exposure to Claritin advertisements increased the efficacy of Claritin (16% at 120 minutes).  This result suggests that advertising can have strong psychologically mediated physiological effects to a drug. 

It is unclear if the results were due to the positive effect of Claritin ads or a negative effect of Zyrtec ads.  A small pilot test included a group that did not receive advertisements, but the authors did not replicate this arm in the larger study.  A follow –up trial should be conducted to determine if positive or negative advertisements have a greater effect as well as a no advertisement control group.

The association of anaphylaxis and chronic pulmonary diseases on hospital outcomes

Mulla et al (BMJ open 2013) sought to determine if chronic pulmonary diseases such as asthma, chronic obstructive pulmonary disease (COPD),  and cystic fibrosis adversely impacted outcomes  in hospitalized patients with various allergic conditions including anaphylaxis.  The authors used data collected from a statewide hospital discharge database, of which 2410 individuals had anaphylaxis. Asthmatics were found to have more than twice the odds of receiving mechanical ventilation and sufferers of chronic bronchitis and COPD had a prolonged hospitalization stay.  The unique analysis of a large database allowed the authors to determine that chronic pulmonary diseases increased the risk of adverse outcomes among hospitalized patients with anaphylaxis. 

The authors did not have access to the complete medical records of the patients, how could this have affected outcomes?

Could there be anaphylaxis coding inconsistencies in hospital databases especially in patients with pulmonary disease?