163 Multi-drug Resistant Organisms(MDRO) are not an Independent Risk Factor for Mortality in Patients with Pneumonia The Importance of Adjusting for Comorbidities and Severity of Illness

Friday, March 19, 2010
Grand Hall (Hyatt Regency Atlanta)
Anupama Vasudevan, BDS , National University Health System, Singapore, Singapore
Douglas Chan, MRCP , National University Health System, Singapore, Singapore
Chee Keat Tan, MMed , National University Health System, Singapore, Singapore
Amartya Mukhopadhay, MRCP , National University Health System, Singapore, Singapore
Paul Ananth Tambyah, MBBS , National University Health System, Singapore, Singapore

Multidrug resistant pathogens (MDRO) including Methicillin resistant Staphylococcus Aureus (MRSA), Extended spectrum beta-lactamase producing gram-negative bacilli (ESBL) and Carbapenem resistant Pseudomonas and Acinetobacter are widespread in hospitals in many parts of the world especially in Asia. These have been associated with a high mortality rate especially in pneumonia including community acquired pneumonia.

Objective: To examine the impact of MDRO and mortality among the patients admitted with Pneumonia to ICU.

Methods: We conducted a prospective observational study to determine the outcomes of patients with community and healthcare associated pneumonia admitted to the medical and surgical ICU of a tertiary teaching hospital in Singapore. All patients admitted to the Surgical and Medical ICU of National University Hospital between Aug 07 and Aug 08 and who had stayed for more than 24 hours were included in the study. Demographics, severity scores, classification according to the IDSA/ATS guidelines and clinical data were collected.

Results: A total of 230 patients were admitted to the ICU with pneumonia during the study period. The mean age of the study population is 61.6±18.5 with 155 (67.4%) being male. 119 (51.7%) of them had Community Acquired Pneumonia, 42.6% had Diabetes, 38% had Renal impairment of which 50% were undergoing Dialysis. The age adjusted Charlson score ranged from 0-13 (median: 4) and APACHEII score from 3-40 (median: 21). 51(22%) of them had MDRO pneumonia – 28 MRSA, 9 ESBL gram negatives,10 and 4 Carbapenem resistant Acinetobacter and Pseudomonas respectively. 40(78%) of these were Hospital acquired.
A multivariate Logistic regression analysis revealed  independent factors associated with mortality as Hospital Acquired Pneumonia (OR:2.6,95%CI:1.46-4.88),Charlson Score >4(OR:3.6,95%CI:1.99-6.75) and APACHE Score >21(OR:2.1,95%CI:1.15-3.91). Infection with MDRO was not associated with increased mortality (OR 1.25, 95% CI 0.56- 2.79, p=0.59)

Conclusions: MDRO infection was not independently associated with mortality in our patients with severe pneumonia admitted to the ICU. It is critical to adjust for severity of illness in analyzing the impact of MDROs in critically ill patients and in determining the appropriateness of initial broad spectrum antimicrobial therapy.