Prediction of community-onset bacteremia among febrile adults visiting an emergency department: Rigor matters

Objectives: Bacteremia is a severe bacterial infection with significant mortality and morbidity. Clinical parameters that reliably predict the presence of community-onset bacteremia are less elucidated. Methods: During 96 randomly selected days between August 2006 and July 2007, a prospective study was conducted to analyze the risk factors of community-onset bacteremia among febrile adults who visited the emergency department (ED) of a medical center. Patients hospitalized in the 30 days prior to the study, patients experiencing consciousness alteration, and nursing facility residents were excluded. Results: The mean age of the 396 febrile adults enrolled in the study was 53.8 years (range, 18-95 years), and 60 (15.2%) patients had true bacteremia, with the predominance of monomicrobial Gram-negative pathogens (42 patients). In a multivariate analysis, several factors were independently associated with community-onset bacteremia, including an age of >65 years (odds ratio [OR], 2.81; 95% confidence interval [CI], 1.25-6.33), the presence of rigor (OR, 13.7; 95% CI, 4.47-42.0) or chills (OR, 6.04; 95% CI, 1.10-32.9), a body temperature >39.9 °C (OR, 2.68; 95% CI, 1.03-6.94), blood urea nitrogen >20 mg/dL (OR, 5.56; 95% CI, 2.03-15.7), a blood urea nitrogen/creatinine ratio >16 (OR, 2.29; 95% CI, 1.03-5.11), and thrombocytopenia (OR, 6.09; 95% CI, 1.84-20.0). After scoring each risk factor, a logistic regression model for the prediction of bacteremia was developed, and the area under the receiver operating characteristic curve was 0.91. Conclusions: Some easily determined clinical parameters were independently associated with community-onset bacteremia among febrile adults, and the most significant predictor was the presence of rigor. Although the proposed predictive model needs further validation, it may be of use for the early identification of bacteremic episodes in ED practice.