Home dust allergen exposures common in patients with COPD

Home dust allergen exposures are common in patients with COPD and exposure is associated with adverse outcomes in those who also have allergen sensitization, researchers reported in American Journal of Respiratory and Critical Care Medicine.

“Environmental pollutant exposures, particularly indoor particulate matter exposures, have been associated with adverse outcomes in COPD, particularly among those with allergic sensitization,” Nirupama Putcha, MD, MHS, associate professor in the division of pulmonary and critical care medicine at Johns Hopkins University School of Medicine, and colleagues wrote. “However, to date, the association of allergen exposures with outcomes in COPD is not clearly known.”

Researchers assessed allergen sensitization to five common indoor allergens: cat, dog, cockroach, mouse and dust mite. The study included 183 former smokers with COPD (mean age, 67.3 years; 44% women). Researchers assessed home-settled dust for the presence of corresponding allergens and determined patients’ sensitization and exposure status, adjusted for symptoms, lung function and exacerbations.

Thirty-three percent of individuals were sensitized to at least one tested allergen: 22% sensitized to dust mite, 21% to cockroach, 11% to cat, 9.8% to dog and 2% to mouse.

Seventy-seven percent of participants were exposed to at least one tested allergen and 17% had sensitization with a corresponding allergen exposure.

Sensitization and exposure were associated with 8.3% lower lung function (beta = –8.29), higher St. George’s Respiratory Questionnaire total score (beta = 6.71) and a more than twofold higher risk for any reported exacerbation (OR = 2.31; 95% CI, 1.11-4.79) after adjustment.

Among participants with lower lung function, these associations appeared more pronounced; individuals with an FEV₁ percent predicted less than 50% had higher associations with risk for any exacerbation (OR = 3.77; 95% CI, 1.45-9.77) compared with individuals with an FEV₁ percent predicted of 50% or more.

“This study highlights the potential value of environmental modification strategies that have the potential to reduce morbidity and health care utilization in patients with COPD and allergic sensitization,” the researchers wrote. “Further studies are still required to better understand the specific allergens that, when targeted and mitigated, have the highest potential to improve outcomes.”