National Trends in Staphylococcus aureus Infection Rates: Impact on Economic Burden and Mortality over a 6-Year Period (1998-2003)

BACKGROUND: We evaluated historical trends in the Staphylococcus aureus infection rate, economic burden, and mortality in US hospitals from 1998 through 2003. METHODS: The Nationwide Inpatient Sample was used to assess trends over time of S. aureus infection during 1998-2003. Historical trends were determined for 5 strata of hospital stays, including all inpatient stays, surgical procedure stays, invasive cardiovascular surgical stays, invasive orthopedic surgical stays, and invasive neurosurgical stays. RESULTS: During the 6-year study period from 1998 through 2003, the rate of S. aureus infection increased significantly for all inpatient stays (from 0. 74% to 1. 0%; annual percentage change (APC), 7. 1%; P=. 004), surgical stays (from 0. 90% to 1. 3%; APC, 7. 9%; P=. 001), and invasive orthopedic surgical stays (from 1. 2% to 1. 8%; APC, 9. 3%; P<. 001). For invasive neurosurgical stays, the rate of S. aureus infection did not change from 1998 to 2000 but increased at an annual rate of 11. 0% from 2000 to 2003 (from 1. 4% to 1. 8%; P=. 034). The total economic burden of S. aureus infection for hospitals also increased significantly for all stay types, with the annual percentage increase ranging from 9. 2% to 17. 9% (P<. 05 for all). In 2003, the total economic burden of S. aureus infection was estimated to be 14. 5 billion for all inpatient stays and 12. 3 billion for surgical patient stays. However, there were significant decreases in the risk of S. aureus-related in-hospital mortality from 1998 to 2003 for all inpatient stays (from 7. 1% to 5. 6%; APC, -4. 6%; P=. 001) and for surgical stays (from 7. 1% to 5. 5%; APC, -4. 6%; P=. 002). CONCLUSIONS: The inpatient S. aureus infection rate and economic burden of S. aureus infections for US hospitals increased substantially from 1998 to 2003, whereas the in-hospital mortality rate decreased.