PURPOSE: The concept of Healthcare-Associated Pneumonia (HCAP) was created to help identify patients presenting to the hospital with pneumonia but who were at risk for pathogens traditionally considered nosocomial in origin. We describe the epidemiology of HCAP and the prevalence of Methicillin resistant Staphylococcus aureus (MRSA) in HCAP.
METHODS: We retrospectively identified patients admitted with pneumonia(Apr 2007 - Mar 2009) at one of 62 US hospitals. The diagnosis of pneumonia was based on ICD-9 codes. We only included patients with lab evidence of bacterial infection (eg, positive sputum, blood, or pleural cultures or urinary antigen testing). We defined as HCAP patients who were admitted from nursing homes, recently hospitalized, required chronic dialysis, or were immunosuppressed. (remainder considered community-acquired pneumonia). The proportion of pneumonias due to HCAP and the prevalence of MRSA in pneumonia served as co-primary endpoints. Need for ICU admission and hospital mortality represented secondary endpoints.
RESULTS: The cohort included 5975 patients (mean age 67.4 yrs; 55.3% male). We noted HCAP in 39.2% of patients and MRSA was identified in 14.0% of the study population. The frequency of MRSA was 1.7 times higher (95% CI: 1.5-2.0, p<0.001) in HCAP. As a screening test for MRSA, the sensitivity, specificity, positive predictive value, and negative predictive value of HCAP were: 52.7%, 63.0%, 18.8%, and 89.1%, respectively. Patients with HCAP were more likely to require ICU care (25.1% vs 22.5%, p=0.020) and to die while hospitalized (17.0% vs. 8.9%, p<0.001). Patients with MRSA, irrespective of pneumonia type, were also more likely to need ICU admission (30.1% vs 22.4%, p<0.001) and to die (18.3% vs. 11.1%, p<0.001).
CONCLUSION: HCAP is common and associated with higher rates of MRSA infection, admission to the ICU, and mortality. MRSA, independent of pneumonia type, remains linked to worse outcomes. HCAP as a screening test for MRSA performs poorly.
CLINICAL IMPLICATIONS: New treatment paradigms are needed to improve outcomes in HCAP. Novel diagnostic approaches are required to facilitate rapid identification of persons presenting to the hospital with MRSA pneumonia.
DISCLOSURE: Andrew Shorr, Grant monies (from industry related sources) Dr. Shorr has recieved grants from Astellas, GSK, J and J, Pfizer, Sanofi.; Shareholder Ms. Myers and Dr. Huang are Pfizer shareholders; Employee Ms. Myers and Dr. Huang are employees of Pfizer and Dr. Emmons and Ms. Yu are employees of Cerner LifeSciences.; Consultant fee, speaker bureau, advisory committee, etc. Dr. Shorr has served as a speaker for or consultant to Astellas, BI, Covdien, Cadence, Canyon, GSK, J and J, Medicines Co. Merck, Pfizer, Sanofi, Theravance; No Product/Research Disclosure Information