Hospitalization decision in febrile intravenous drug users

To determine the frequency and to identify predictive factors of occult major illness in febrile intravenous drug users (IVDUs) presenting to an emergency room.

A prospective follow-up study was performed involving a consecutive series of 296 presentations of febrile IVDUs to a public hospital emergency room. Follow-up information was obtained for 283 presentations (95.6%). Physician's initial assessment was obtained for 204 presentations (70%). Illness was classified as major or minor using explicit criteria. Frequency of occult major illness was determined among patients without obvious major illness on presentation. Risk factors for occult major illness were determined.

Occult major illness occurred in 11 patients (4%). This represented 11% of the 103 presentations without obvious major illness on presentation. Pneumonia and cellulitis occurred in 128 of 180 patients (71%) with obvious major illness on presentation. Bacteremia was present in seven of 11 patients with occult major illness. Physician predictions were not sufficiently sensitive to provide the basis of the hospitalization decision in febrile IVDUs. The best combination of features suggesting major illness were last use of intravenous drugs less than 5 days and fever greater than 38.8 degrees C (102.0 degrees F) (sensitivity 64%, specificity 77%).

Clinical tests and physician assessments are unable to distinguish occult major illness from minor illness among febrile IVDUs at presentation. Occult major illness is best identified by blood culture. If patient follow-up is unreliable, then hospitalization of febrile IVDUs, while awaiting blood culture results, remains a wise policy.