[Use of the French medico-administrative database (PMSI) to detect nosocomial infections in the University hospital of Lyon].

Background: Surveillance is an effective element in the fight against nosocomial infections, but the monitoring methods are often cumbersome and time consuming. The detection of infection in computerized databases is a means to alleviate the workload of health care teams. The objective of this study was to evaluate the performance of using discharge summaries in medico-administrative databases (PMSI) for the identification of nosocomial infections in surgery, intensive care and obstetrics.

Methods: The retrospective assessment study included patients who were hospitalized in general surgery, intensive care and obstetrics at different periods of time in 2006 and 2007 depending on the wards. Patients were monitored according to standard protocols which are coordinated at the regional level by the Southeast coordinating centre (CCLIN). The performance of identifying cases of nosocomial infection from discharge diagnoses coded by using the International Classification of Diseases (tenth revision) was evaluated by a study of sensitivity, specificity, positive and negative predictive values with their 95% confidence intervals.

Results: Using a limited number of diagnostic codes, the sensitivity and specificity were, respectively, 26.3% (95% CI 13.2-42.1) and 99.5% (95% 98.8-100.0) for the identification of surgical site infections. By expanding the number of diagnostic codes, the sensitivity and specificity were 78.9% (95% CI 65.8-92.1) and 65.7% (95% CI 61.0-70.3). The sensitivity and specificity for case identification of nosocomial infections in intensive care were 48.8% (95% CI 42.6-55.0) and 78.4% (95% CI 76.1-80.1), and were 42.9% (95% CI 25.0-60.7) and 87.3% (95% CI 85.2-89.3) for identification of postpartum infections.

Conclusion: The PMSI is not a sufficiently efficient method in terms of sensitivity to be used in surveillance of nosocomial infections. A reassessment of the PMSI must be considered, with changes in coding of comorbidity that occurred in 2009.