A Mixed Model for Invasive MRSA Rates Analysis Among EIP Sites

• Activity Number: 257
• Type: Contributed
• Date/Time: Monday, August 2, 2010 : 2:00 PM to 3:50 PM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): Yi Mu*+ and Jonathan R. Edwards and Scott Fridkin
• Companies: CDC and CDC and CDC
• Keywords: MRSA ; Mixed Model ; Statistical Model

Abstract

Reports of invasive methicillin-resistant S. aureus (MRSA) infections from 9 metropolitan sites participating in CDC's population-based surveillance for MRSA from 2005-2007 were classified as hospital onset (HO), hospital associated community onset (HACO) or community-associated (CA) based on timing of infection and exposure to healthcare. Evaluation of changes in incidence over time was traditionally made based on aggregated data across sites. This method masks important variations and patterns within data and ignores the influences of variations in risk populations between sites. We demonstrate how a mixed model analysis addresses these limitations. The results showed: 1) Estimated overall HO, HACO rates decreased during study periods, while CA rates remained unchanged, and 2) Race accounted for most of the inter-site differences for CA and HACO and was less important for HO.