Allergic disease worsens respiratory symptoms and exacerbations in COPD

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.

What is COPD?

Chronic Obstructive Pulmonary Disease (COPD) is not one single disease but an umbrella term used to describe chronic lung diseases that cause limitations in lung airflow. The more familiar terms 'chronic bronchitis' and 'emphysema' are no longer used, but are now included within the COPD diagnosis.

The most common symptoms of COPD are breathlessness, or a 'need for air', excessive sputum production, and a chronic cough. However, COPD is not just simply a "smoker's cough", but a under-diagnosed, life threatening lung disease that may progressively lead to death.
Main risk factors for COPD

Tobacco smoking
Indoor air pollution (such as biomass fuel used for cooking and heating)