Patients with chronic obstructive pulmonary disease (COPD)
who also have allergic disease have higher levels of respiratory
symptoms and are at higher risk for COPD exacerbations, according to a
new study from researchers at Johns Hopkins University in Baltimore.
“Although
allergic sensitization and allergen exposure are known to be associated
with impairments in lung function, the effects of allergic disease on
respiratory symptoms in COPD patients has only recently been studied,”
said researcher Nadia N. Hansel, MD, MPH, associate professor of
medicine at the Johns Hopkins Asthma & Allergy Center. “Accordingly,
we examined the effects of allergic disease on respiratory health in
two sets of patients with COPD, one a nationally representative sample
of 1,381 COPD patients from the National Health and Nutrition Survey III
(NHANES III) and the other a cohort of 77 former smokers with COPD from
a study of the effects of endotoxin exposure on health status.”
“We
found that COPD patients with an allergic phenotype had an increased
risk of lower respiratory symptoms and respiratory exacerbations.”
The findings were published online ahead of print publication in the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.
In
the NHANES III cohort, 296 COPD patients had an allergic phenotype,
which was defined as self-reported doctor-diagnosed hay fever or
allergic upper respiratory symptoms. These patients were significantly
more likely to wheeze, have chronic cough, and have chronic phlegm and
had a significantly increased risk of experiencing a COPD exacerbation
that required an acute visit to the doctor.
In the second cohort
of 77 COPD patients, the 23 patients with allergic sensitization
(determined by immunoglobulin E testing) were significantly more likely
to wheeze, to experience nighttime awakening due to cough, and to have
COPD exacerbations requiring antibiotic treatment or an acute visit to
the doctor.
“Our findings in two independent populations that
allergic disease is associated with greater severity of COPD suggest
that treatment of active allergic disease or avoidance of allergy
triggers may help improve respiratory symptoms in these patients,
although causality could not be determined in our cross-sectional
study,” said Dr. Hansel.
There were a few limitations to the
study, including possible misclassification of COPD in some NHANES
patients and the use of self-reported respiratory symptoms and COPD
exacerbations.
“Current COPD guidelines do not address the
management of allergic disease in COPD patients,” Dr, Hansel said.
“Additional studies of the relationship between allergic disease and
COPD are clearly needed.”
To read the article in full, please visit: http://www.thoracic.org/media/press-releases/resources/Hansel.pdf.
Source: Newswise