Association of prehospitalization aspirin therapy and acute lung injury: Results of a multicenter international observational study of at-risk patients

Objective: To evaluate the association between prehospitalization aspirin therapy and incident acute lung injury in a heterogeneous cohort of at-risk medical patients. Design: This is a secondary analysis of a prospective multicenter international cohort investigation. Setting: Multicenter observational study including 20 US hospitals and two hospitals in Turkey. Patients: Consecutive, adult, nonsurgical patients admitted to the hospital with at least one major risk factor for acute lung injury. Interventions: None. Measurements and Main Results: Baseline characteristics and acute lung injury risk factors/modifiers were identified. The presence of aspirin therapy and the propensity to receive this therapy were determined. The primary outcome was acute lung injury during hospitalization. Secondary outcomes included intensive care unit and hospital mortality and intensive care unit and hospital length of stay. Twenty-two hospitals enrolled 3855 at-risk patients over a 6-month period. Nine hundred seventy-six (25.3%) were receiving aspirin at the time of hospitalization. Two hundred forty (6.2%) patients developed acute lung injury. Univariate analysis noted a reduced incidence of acute lung injury in those receiving aspirin therapy (odds ratio [OR], 0.65; 95% confidence interval [CI], 0.46-0.90; p = .010). This association was attenuated in a stratified analysis based on deciles of aspirin propensity scores (Cochran-Mantel-Haenszel pooled OR, 0.70; 95% CI, 0.48-1.03; p = .072). Conclusions: After adjusting for the propensity to receive aspirin therapy, no statistically significant associations between prehospitalization aspirin therapy and acute lung injury were identified; however, a prospective clinical trial to further evaluate this association appears warranted.