Inpatient treatment patterns, outcomes, and costs of skin and skin structure infections because of Staphylococcus aureus

Background

Staphylococcus aureus (SA) is a common bacterial pathogen in skin and skin structure infections (SSSIs). Limited data exist on hospital treatment patterns and costs for SA-SSSIs.

Methods

This retrospective analysis examined the lengths of stay, treatment patterns, and costs of hospitalized patients with an SA-SSSI diagnosis using a nationally representative inpatient database. Patients were selected if they had an ICD-9-CM diagnosis of an SSSI with SA noted between January 2005 and June 2006, received a study antibiotic (ie, intravenous [IV] vancomycin, IV or oral linezolid, and IV daptomycin), and were not in the intensive care unit before receiving a study antibiotic. Generalized linear models assessed predictors of length of stay and costs. Costs are expressed in 2005 US dollars.

Results

Thirteen thousand four hundred thirty-three patients met the selection criteria and mean (±SD) age was 48.2 (±18.3) years. Forty percent of patients received a nonstudy antibiotic before receiving their first study antibiotic. Ninety-five percent were prescribed vancomycin as their first study antibiotic. Study antibiotics were administered for an average of 4.3 days, and 8% of patients switched study antibiotics. Nineteen percent of patients receiving IV linezolid stepped down to oral linezolid. Mean (±SD) lengths of hospital stay and costs were 6.1 (±6.0) days and $6830 (±$7100). In-hospital mortality, switching antibiotics, and diagnoses of selected complications or comorbidities were associated with increased lengths of stay and costs. Younger age, location outside the Northeast, and use of oral linezolid were associated with lower lengths of stay and costs.

Conclusion

The costs of treating inpatient SA-SSSIs are substantial and vary by patient demographics and treatment characteristics.

Key Words: Economics, antibiotics, outcomes