(RxWiki News) Many patients with chronic obstructive pulmonary disease (COPD) experience episodes called exacerbations in which their symptoms get worse. New research suggests that allergies may add to these symptoms.
Results of a recent study showed that COPD patients who also had allergies were more likely to have upper respiratory symptoms such as wheezing, chronic cough and chronic phlegm.
COPD patients with allergies also appeared to have an increased risk of experiencing COPD exacerbations.
"See your doctor if your COPD symptoms worsen."
From this study, Nadia N. Hansel, MD, MPH, of the Johns Hopkins University Asthma & Allergy Center in Baltimore, Maryland, and colleagues wanted to find out if allergies contributed to respiratory symptoms (related to the lungs and breathing) and exacerbations in people with COPD.
COPD is the name for a group of lung conditions that block airflow and make it hard to breathe. The two most common forms of COPD are emphysema and chronic bronchitis.
"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 Dr. Hansel.
So Dr. Hansel and colleagues set out to expand on this research. "[W]e 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," Dr. Hansel explained.
Of the NHANES III group, 296 patients reported being diagnosed with hay fever or allergic upper respiratory symptoms by a doctor.
The researchers found that these patients with allergies had 2.1 times higher odds of having a wheeze, 1.9 times higher odds of having a chronic cough and 1.5 times higher odds of having chronic phlegm, compared to COPD patients without allergies.
Furthermore, the allergic patients had 1.7 times higher odds of having COPD exacerbations that required a doctor visit.
When studying the group of former smokers with COPD, the researchers determined which patients had year-round allergies by measuring blood levels of immunoglobulin E (IgE), a type of antibody.
Of the 77 former smokers, 23 had allergies. These allergic patients had 5.91 times higher odds of wheeze and 4.20 times higher odds of waking during the night due to cough.
These allergic former smokers with COPD also had 3.79 times higher odds of of experiencing COPD exacerbations that required treatment with antibiotics and 11.05 times higher odds of acute health visits (seeking care for a specific complaint).
According to Dr. Hansel, "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."
There were some limitations to this study, primarily related to the classification of COPD in some NHANES participants and self-reporting of respiratory symptoms and COPD exacerbations.
"Current COPD guidelines do not address the management of allergic disease in COPD patients," said Dr. Hansel. Therefore, more research is needed to better understand the relationship between allergies and COPD, she said.
This study was published online ahead of print in May in the American Journal of Respiratory and Critical Care Medicine.
The research was supported by grants from the National Institute of Environmental Health Sciences. No author disclosures were reported.