Risk factors for severe sepsis in secondary peritonitis.

BACKGROUND The incidence and risk factors for severe sepsis (SS, organ failure associated with infection) in the context of peritonitis are not well established; thus, it is not clear which patients require more aggressive operative or pharmacologic intervention. We set out to determine risk factors for severe sepsis in a large cohort of patients with intra-abdominal infection. METHODS Patients admitted for peritonitis over a four-year interval were identified using a Washington State administrative hospital discharge database. This cohort was identified by ICD-9 CM diagnoses and diagnosis-related group (DRG) assignment. Patients with organ failure were identified by ICD-9 CM diagnoses codes using a previously validated classification scheme. Independent risk factors for SS were identified using stepwise Poisson regression. RESULTS A total of 11,202 patients with peritonitis were identified, 11% of whom developed SS. The crude relative risk of death in patients with SS was 13 (95% CI, 11.1-15.2) times greater than those without. Severe sepsis was present in 424 (62%) of the 686 decedents. Multivariate analysis showed that source of infection, extent of peritonitis, increasing age, and pre-existing organ dysfunction were independently associated with SS. CONCLUSIONS Severe sepsis complicates the course of 11% of all patients with peritonitis. Risk factor analysis identifies a subset of patients at greatest risk for severe sepsis. These are the patients who should be targeted for evaluation of novel pharmacologic interventions or more aggressive surgical intervention.