Pre-hospital use of inhaled corticosteroids and inhaled beta agonists and incidence of ARDS: A population-based study.

OBJECTIVE Inhaled corticosteroids and inhaled beta agonists were shown to decrease the lung injury in animal models. We investigated the association of pre-hospital use of inhaled corticosteroids and inhaled beta agonists with the incidence of Acute Respiratory Distress Syndrome (ARDS) in a population based cohort of hospitalized patients. MATERIAL AND METHODS Retrospective cohort study of adult patients from Olmsted County, Minnesota admitted to the hospital with at least one predisposing condition for ARDS from 2001-2008. The association with pre-hospital use of inhaled corticosteroids and inhaled beta agonists was evaluated using univariate and multivariate analyses. Primary outcome was ARDS and secondary outcome was hospital mortality. RESULTS Out of 2429 hospitalized adult patients with at least one risk factor for ARDS, 10.5% of those taking and 14% of those not taking inhaled corticosteroids developed ARDS (OR 0.72; 0.53-0.97; p<0.03). Inhaled beta agonists showed similar unadjusted protective effect; 9.7% of users and 14.4% of non-users developed ARDS (OR 0.64; 0.48-0.86; p=0.003). After adjusting for risk factors, comorbidities and severity of illness in the multiple logistic regression model, use of inhaled beta agonists, but not inhaled corticosteroids, remained independently associated with decreased risk of ARDS (OR 0.48; 0.31-0.72; p<0.001 versus 0.87; 0.57-1.29; p=0.49). The estimated protective effects were more pronounced among patients with pneumonia compared to those without pneumonia. CONCLUSION Prehospital use of inhaled beta agonists but not inhaled corticosteroids was significantly associated with decreased incidence of ARDS among hospitalized patients at risk, once adjusted for baseline characteristics, predisposing and comorbid conditions, as well as severity of illness.