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Objective:
The aim of this
study was to
evaluate the
predictive value of
lung function and
fraction of exhaled
nitric oxide (FeNO)
for difficult asthma
in children.
Patients and
Methods:
Children with asthma
referred to an
asthma clinic for
uncontrolled
persistent asthma on
inhaled
corticosteroids
(ICSs) alone or in
combination with a
long-acting
ß2-agonist and/or a leukotriene receptor
antagonist were
followed in a
prospective
1-year study to
identify difficult
asthma. At the end
of the study period,
difficult asthma was
considered for
children with
persistent asthma
symptoms and/or
frequent
moderate/severe
asthma exacerbations
despite regular
intake of ICSs (beclomethasone
or equivalent)>800
μg/d for at least 3
months, after
correcting for
adherence to
treatment,
inhalation
technique, and
comorbidities and
after implementing
an individualized
treatment plan. The
difficult asthma
phenotype was
characterized using
a multidimensional
approach combining
clinical features
and pathophysiologic
features (lung
function and
inflammation).
Unfavorable lung
function trend
(persistent airway
obstruction and
fluctuations in
forced expiratory
volume in the first
second of α>0.5) and
persistently high
FeNO levels (>45 ppb
despite increasing
ICS doses) were
analyzed as risk
factors for
difficult asthma in
the logistic
regression analysis
together with male
sex, atopy,
concurrent severe
rhinitis, obesity,
psychopathology,
exposure to tobacco
smoke, low
socioeconomic
status, lack of
adherence to
treatment, and
persistent
bronchodilator
response.
Results:
Forty-six asthmatic
children (34 males,
74%) with a mean (SEM)
age of 7.55 (3.04)
years were enrolled.
After 1 year, 24
children (52%) were
labeled as having
diffi cult asthma.
Independent risk
factors for
difficult asthma
were persistently
high FeNO (P=.04),
obesity (P=.04),
and severe rhinitis
(P=.03).
Conclusions:
Persistently high
FeNO predicts
difficult asthma in
children, while
unfavorable lung
function trend does
not.
Key words:
Asthma. Disease
exacerbation.
Inflammation. Lung
function tests. Risk
factors. |
