Fever of unknown origin: differential diagnosis between infectious and non-infectious causes

Abstract number: P893

Efstathiou S.P., Pefanis A.V., Tsiakou A.G., Skeva I.I., Tsioulos D.I., Achimastos A.D., Mountokalakis T.D.

Objective: The aims of the present study were (a) to develop a simple and reliable diagnostic model that could aid physicians to discriminate between infectious and non-infectious causes of fever of unknown origin (FUO), and (b) to evaluate the performance of the derived tool in an independent database of subjects with FUO.

Methods: Participants were patients with classical FUO fulfilling the modified criteria of Durack and Street. Data were prospectively gathered in two distinct, observational phases: an internal developmental study (from 1992 to 2000) and an external validation study (from 2001 to 2007). In the internal phase, 33 variables regarding each patient's demographic characteristics, history, symptoms, signs, and laboratory profile were recorded and considered in a logistic regression analysis using the diagnosis of infection as dependent variable. In the external phase, the model derived on the basis of the independent predictors of diagnosis of infection was applied on the next consecutive subjects with FUO and the respective discriminatory capacity was calculated.

Results: Data from 112 hospitalised individuals (mean age 56.5±11.2 years, 55% males, fever duration before admission 32.1±11.9 days) were analyzed in the internal study. The final diagnoses included infections, malignancies, non-infectious inflammatory diseases, and miscellaneous conditions in 30.4%, 10.7%, 33% and 5.4% of subjects, whereas 20.5% of cases remained undiagnosed. C-reactive protein >60 mg/L (odds ratio 6.0 [95% confidence intervals 2.5, 9.8]), eosinophils <40/mm3 (4.1 [2.0, 7.3]) and ferritin <500 mg/L (2.5 [1.3, 5.2]) were independently associated with diagnosis of infection. Among the 100 patients of the external study, the presence of geqslant R: gt-or-equal, slanted 2 of the above factors predicted infection with sensitivity, specificity, and positive and negative predictive values of 91.4%, 92.3%, 86.5%, and 95.2%, respectively. Thus, the overall discriminatory capacity of the model – when the cut-off of geqslant R: gt-or-equal, slanted2 factors was used – corresponded to an area under the curve (AUC) of 0.92 (95% CI 0.85, 0.98; p < 0.001), whereas the respective AUC values of its three components were 0.75 for C-reactive protein [95% CI 0.65, 0.86], 0.70 for eosinopenia [0.59, 0.80], and 0.68 for ferritin [0.57, 0.78]).

Conclusions: The combination of C-reactive protein, ferritin and eosinophil count may be useful in discriminating infectious from non-infectious causes in patients hospitalised for classical FUO.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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