Epidemiology and impact of aspiration pneumonia in patients undergoing surgery in Maryland, 1999-2000

Objective: The epidemiology of aspiration pneumonia and its impact on clinical and economic outcomes in surgical patients are poorly defined. We sought to identify preoperative patient characteristics and surgical procedures that are associated with an increased risk for aspiration pneumonia and to determine the clinical and economic impact in hospitalized surgical patients. Design: Observational study using a state discharge database. Setting: All hospitals in Maryland. Patients: We obtained discharge data for 318,880 adult surgical patients in 52 Maryland hospitals from January 1, 1999, through December 31, 2000. Measurements and Main Results: The primary outcome variable was a discharge diagnosis of aspiration pneumonia. Unadjusted and adjusted analyses were performed to identify patient characteristics and surgical procedures associated with an increased risk for aspiration pneumonia and to determine the impact on intensive care unit admission, in-hospital mortality, hospital length of stay, and total hospital charges. The overall prevalence of aspiration pneumonia was 0.8%. The prevalence varied among hospitals (range, 0% to 1.9%) and by surgical procedure (range, <0.1% to 19.1%). Patient characteristics independently associated with an increased risk included: male sex, nonwhite race, age of >60 yrs vs. 18-29 yrs, dementia, chronic obstructive pulmonary disease, renal disease, malignancy, moderate to severe liver disease, and emergency room admission. In patients undergoing procedures other than tracheostomy, aspiration pneumonia was independently associated with an increased risk for admission to the intensive care unit (odds ratio, 4.0; 95% confidence interval, 3.0-5.1), in-hospital mortality (odds ratio, 7.6; 95% confidence interval, 6.5-8.9), longer hospital length of stay (estimated mean increase of 9 days; 95% confidence interval, 8-10), and increased total hospital charges (estimated mean increase of $22,000; 95% confidence interval, $19,000-$25,000). Conclusions: Aspiration pneumonia occurs in approximately 1% of surgical patients and is associated with significant morbidity, mortality, and costs of care. Given that the rate of aspiration pneumonia varies among hospitals, we can improve the quality and reduce the costs of care by implementing strategies to reduce the rate of aspiration pneumonia.