Outcomes and costs associated with monomicrobial and polymicrobial pathogens in patients with skin and skin structure infections

Abstract number: P820

Akhras K.S., Lin S., Quintana A., Hatoum H.T.

Introduction: Although skin and skin structure infections (SSSIs) are caused predominantly by Gram-positive pathogens, polymicrobial infections and multidrug-resistant (MDR) pathogens are becoming a growing concern. Little is published about outcomes associated with monomicrobial versus polymicrobial SSSI.

Objective: To compare length of hospital stay (LOS) and hospital charges associated with monomicrobial and polymicrobial infections in patients with SSSI.

Methods: This retrospective analysis used Thomson MedSTAT data from the United States from 2001 to 2005. Patients 18 years of age hospitalised 2 days with a primary or secondary diagnosis of SSSI were identified using ICD-9 codes. Microbiology data were used to classify patients into microbiologically evaluable (ME) and non-microbiologically evaluable (non-ME). ME patients with infections were further classified into Gram-positive, Gram-negative, monomicrobial, and polymicrobial infections. Outcomes variables were LOS, total days of IV antibiotics and total hospitalisation charges.

Results: Of the 1,472,965 hospitalisations, 44,743 cases were identified as SSSI of which 5403 (12.1%) were ME. The overall unadjusted mean and median LOS and total charges for SSSI cases were 9.4 and 6 days and $40,150 and $ 20,911. Overall mean days of IV antibiotics therapy was 8 days. The table reports results by pathogen type for ME SSSI cases.

Unadjusted LOS and total hospitalisation charges by pathogen type

Conclusion: In this large database, SSSI type infections caused by polymicrobial pathogens were associated with longer LOS, longer treatment duration with IV antibiotics, and higher total charges compared with monomicrobial infections.