Mild Asthma Patients Can Improve Lung Function With Treatment

Patients with very mild or well-controlled asthma can significantly
improve day-to-day lung function if regularly treated with low dose
inhaled corticosteroids (ICS), according to a new study published in Primary
Care Respiratory
. The study was conducted by researchers at the
Woolcock Institute of Medical Research in Sydney, Australia.

Asthma is a respiratory condition in which the airway constricts,
become inflamed, and is lined with excessive amounts of mucous. Inhaled
corticosteroids that suppress inflammation and reduce the swelling of
the airway lining are commonly prescribed to help prevent asthma. The
Australian researchers conducted a study over an 11 month period in
order to compare the effects of ICS and placebo on asthma control in
mild asthmatics.

The results of the randomized, double-blind placebo study showed
significant and clinically important treatment benefits of ICS
on several markers. These include lung function, airway
hyperresponsiveness and
exhaled nitric oxide – all predictors of exacerbation (asthma attack)
risk and other adverse outcomes. Currently asthma treatment is based on
controlling symptoms, but it does not recommend ICS treatment if
patients only have symptoms two days a week or less. The authors
suggest that the results of this study lead to questions about the
appropriate treatment and prevention strategies.

Further, results indicated that contrary to common beliefs about mild
asthma, there is no “ceiling” effect for lung function. For patients
whose lung function is over 90% of predicted normal value, there may be
room for improvement if treated.

“While we’re not advocating that every patient with mild asthma should
be on preventer medication, the study shows that when we are discussing
the risks and benefits of treatment with these patients, we should talk
about their risk of future exacerbations as well as whether they will
notice any difference in their current symptoms,” writes research
leader Assoc. Prof. Helen Reddel.

Study participants who received placebo were almost 3 times as more
likely to experience a mild exacerbation.

Reddel comments that: “In recent years the emphasis in asthma treatment
has been on how well
a patient’s symptoms are controlled.” In this study, the patients had
asthma that was so mild “with symptoms
once a week or less, that they themselves didn’t see any benefit in
regular preventer treatment.”

“However for those participants receiving ICS during the study, their
lung function was better, they had less airway inflammation and less
airway twitchiness. All of these things are predictors of reduction in
risk of future adverse outcomes.” Although the sample size was small,
the authors were able to get
measurements of airway twitchiness, airway inflammation and daily
spirometry. These data are useful in determining future risk and are
often not easily obtainable in larger groups.

Does continuous use of inhaled corticosteroids improve
outcomes in mild asthma? A double-blind randomised controlled trial
Helen K Reddel, Elena G Belousova, Guy B Marks, Christine R
Primary Care Respiratory Journal. (2008).
doi: 10.3132/pcrj.2008.00014
Here to View Abstract

Written by: Peter M Crosta

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