318. Epidemiology of Infectious Encephalitis, Differences Between Prospective and Hospital Discharge Data in France in 2007
Session: Poster Abstract Session: Assessing and Reducing Infection Risk
Friday, October 21, 2011
Room: Poster Hall B1

The epidemiology of infectious encephalitis has been described through hospital discharge database and few prospective studies. The aim of our work was to compare the results from the French national hospital discharge database (Programme de Médicalisation des Systèmes d’Information, PMSI) and from a French multicentric prospective study in 2007 (Mailles et al in 2007) to evaluate if PMSI could be used for the surveillance of encephalitis.


Encephalitis cases were identified in the PMSI using ICD10 codes. The demographic characteristics, the distribution of causative agents and the case-fatality ratio were compared between the PMSI and the study using STATA11®.


253 cases were included in the study and 1694 cases were identified from the PMSI in 2007. Causes were identified for (131/253, 52%) and (647/1694, 38%) (p<0,001). Herpes simplex virus (HSV) and Varicella zoster virus (VZV) were the most frequent etiological agents in both databases with comparable frequencies. The distribution of less frequent germs was also similar (Borrelia burgdorferi, Mycoplasma pneumoniae, Cytomegalovirus). The demographical data (age, sex), hospital length of stay were not significantly different. The case-fatality ratio was not different in both databases, overall and by germs.  Listeria monocytogenes (LM) and Mycobacterium tuberculosis (MT) were significantly less frequent in PMSI than in the prospective study (LM: 2% vs 5%, p=0.001; MT 2% vs 8%, p=10-9 ). Cases with no etiological diagnosis were more frequent in the PMSI but their demographical data and case-fatality ratio did not differ from those obtained from the study. 


To our knowledge no previous work had compared these 2 types of data. Data from the PMSI probably have some limitations due to the absence of case definition and to the possible misclassification of meningitis in encephalitis. However our results suggest that PMSI may be used as a basic surveillance tool with limited costs. It is crucial to know its limitations to correctly interpret results from this type of database and use them for surveillance.

Subject Category: N. Hospital-acquired and surgical infections, infection control, and health outcomes including general public health and health services research

Sylvain Bernard, Infectious Diseases, University Hospital and Grenoble University, Grenoble, France, Alexandra Mailles, French Institute for Public Health (INVS), Saint Maurice, 94415, France and Jean Paul Stahl, Infectious Diseases, University Hospital and Grenoble University, Grenoble, 38043, France


S. Bernard, None

A. Mailles, None

J. P. Stahl, None

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