Clinical and Economic Outcomes Attributable to Health Care-Associated Sepsis and Pneumonia

Background: Health care-associated infections affect 1.7 million hospitalizations each year, but the clinical and economic costs attributable to these infections are poorly understood. Reliable estimates of these costs are needed to efficiently target limited resources for the greatest public health benefit. Methods: Hospital discharge records from the Nationwide Inpatient Sample database were used to identify sepsis and pneumonia cases among 69 million discharges from hospitals in 40 US states between 1998 and 2006. Community-acquired infections were excluded using criteria adapted from previous studies. Because these criteria may not exclude all community-acquired infections, outcomes were examined separately for cases associated with invasive procedures, which were unlikely to result from preexisting infections. Attributable hospital length of stay, hospital costs, and crude in-hospital mortality were estimated from discharge records using a multivariate matching analysis and a supplementary regression analysis. These models controlled for patient diagnoses, procedures, comorbidities, demographics, and length of stay before infection. Results: In cases associated with invasive surgery, attributable mean length of stay was 10.9 days, costs were $32900, and mortality was 19.5% for sepsis; corresponding values for pneumonia were 14.0 days, $46400, and 11.4%, respectively (P<.001). In cases not associated with invasive surgery, attributable mean length of stay, costs, and mortality were estimated to be 1.9 to 6.0 days, $5800 to $12700, and 11.7% to 16.0% for sepsis and 3.7 to 9.7 days, $11100 to $22300, and 4.6% to 10.3% for pneumonia (P<.001). Conclusion: Health care-associated sepsis and pneumonia impose substantial clinical and economic costs.