Morgan DJ (VA Maryland Health Care System), Day HR
(VA Maryland Health Care System), Strauss SM
(VA Maryland Health Care System), Schweizer ML
(VA Maryland Health Care System), Roghmann M
(VA Maryland Health Care System), Perencevich EN
(VA Maryland Health Care System)
Clinical prediction rules have been used to efficiently identify patients at high risk of colonization with Methicillin-Resistant Staphylococcus Aureus (MRSA) or Vancomycin-Resistant Enterococci (VRE). In 2007, the VA mandated active surveillance for all patients admitted to acute-care hospitals. This mandate, while targeting patient safety, is expensive. If high-risk patients can be identified using a simple prediction rule and targeted for MRSA (and also VRE) screening, it might be more cost-effective. We have developed, validated and implemented a clinical prediction rule at the University of Maryland that identifies 80% of patients with MRSA, while limiting expensive culture to only 50% of admitted patients, saving the hospital approximately $200,000 annually. We aimed to determine the clinical efficacy of similar prediction rules in a Veterans Hospital.
We are conducting a prospective cohort study of all adult inpatients admitted to the medical and surgical wards of a tertiary-care VA hospital. In the first 48 hours of admission, patients were approached for consent, administered a 44-item questionnaire, and received nasal and peri-rectal cultures for MRSA and VRE, respectively. We report an interim analysis.
Out of the initial 341 patients enrolled, 331 underwent nasal cultures and 241 underwent peri-rectal cultures. Overall, 14% were MRSA positive and 7% were VRE positive. Patient self-report of having received antibiotics in the past year was the most sensitive single predictor for MRSA (71%); specificity was 50% (relative risk (RR) = 2.2 (95% CI 1.2 - 4.0), p = 0.014. This rule had a sensitivity of 81% for VRE (RR = 3.7 (95% CI 1.1 – 12.6), p = 0.04. Use of this predictor would require swabbing only 53% of admissions. A prediction rule using self-report of hospitalization or receiving antibiotics in the past year would have identified 80% and 94% of patients colonized with MRSA or VRE, respectively, and require swabbing 70% of admissions.
Patient self-report of receiving antibiotics within the past year identifies a group of patients at high risk for colonization with MRSA or VRE that could be considered for targeted active surveillance culturing.
This approach has the potential for significant cost-savings compared to the current practice of universal active surveillance.