FeNO use in asthma monitoring - summary from 2011 CSACI meeting

This summary was compiled from tweets posted by Dr. Stuart Carr @allergydoc4kidz, the president of the Canadian Society of Allergy and Clinical Immunology (CSACI). The tweets were labeled #CSACI and they reached more than 10,000 people. I would strongly encourage you to post updates on Twitter from the CME conferences that you are planning to attend in the future.

This summary is from the debate on FeNO (Jonathon Malka) vs. sputum eos (Param Nair) in asthma monitoring.

Pros

FeNO can be helpful in children with suggestive symptoms for asthma but normal lung function. Elevated FeNO predicts better inhaled steroid response, and may increase the acceptance of anti-inflammatory therapy (ICS).

FeNO can be helpful in distinguishing poor asthma control vs. confounders such as GERD.

FeNO can be a useful marker of adherence, and it can prevent unnecessary investigations or therapy changes.

A persistently elevated FeNO is associated with lung function loss over time (according to the TREXA study).

FeNO helps the diagnosis of primary ciliary dyskinesia - if very low in both nose and lungs.

Cons

However, FeNO-based therapy does not decrease asthma exacerbations. FeNO levels are not well correlated with eosinophil levels (based on an anti-IL5 study). It may not tell us what we've assumed - that elevated FeNO is associated with eosinophil infiltrate in bronchial mucosa.

There are too many factors that impact FeNO (including sham odor exposure) to be consistently useful.

Persistent sputum eosinophilia predicts favorable clinical response to anti-IL5.

Disclaimer: The text was edited, modified, and added to by me. I was invited to speak on the topic of social media use by the allergists during the 2011 CSACI meeting.

Related reading:

Inflammometry: the current state of play in asthma - FeNO and more. Thorax, 2012.
In the UK, FeNO is used in primary practice to guide ICS initiation, dosing and identify poor ICS adherence http://buff.ly/1aHKopT