Chronic obstructive pulmonary disease and risk of infection.

This review article focuses on the risk of infections in patients with chronic obstructive pulmonary disease (COPD). Throughout the years there have been a number of studies describing the risk of pulmonary infections in patients with COPD, whereas only few studies have focused on the risk of infection outside the lungs. With increasing severity of COPD the risk of respiratory tract infection also increases. The impairment of the innate immune system is most likely responsible for both the colonization of respiratory tract with bacteria and for an increased risk of infection with new strains of bacteria causing acute exacerbations. Also lung infections like pneumonia, lung abscess and empyema are more often seen in patients with COPD than in healthy subjects. With regard to extrapulmonary infections, it seems that COPD patients are not at higher risk of infection compared with subjects without COPD. It is concluded that COPD is significantly associated with an increased risk of various respiratory tract infections, but not with infections outside the respiratory system.