Inhaled drugs as risk factors for community-acquired pneumonia.

The effect of inhaled drugs in community-acquired pneumonia (CAP) is unclear. This case-control study was designed to determine whether inhaled drugs were risk factors for CAP. All incident cases of confirmed CAP that occurred over 1 yr in patients with chronic bronchitis (CB), chronic obstructive pulmonary disease (COPD) or asthma were included, as well as CB, COPD and asthma controls. Risk factors for CAP and inhaled treatment were recorded during a personal interview. An effect of inhaled drugs on the risk of CAP was observed in COPD and asthma patients after adjusting for the effect of other respiratory diseases and their concomitant treatments. In COPD patients, inhaled steroids had a risk OR of 3.26 (95% CI 1.07-9.98) and in asthma patients inhaled anticholinergics had a risk OR of 8.80 (95% CI 1.02-75.7). In CB patients, no association with CAP was observed for any inhaler. These effects were independent of adjusting variables related to severity and other respiratory and non-respiratory risk factors for CAP, including vaccines. Inhaled β(2)-adrenergic agonists did not show a significant effect on the risk of CAP in any of the respiratory diseases. Inhaled steroids may favour CAP in COPD patients, whereas anticholinergics may favour CAP in asthma patients. It is difficult to differentiate the effect of inhaled therapy from the effect of COPD or asthma severity on the risk of CAP, and these relationships may not be causal, but could call attention to inhaled therapy in COPD and asthma patients.