LAUSR

BACKGROUND Although blood cultures (BCs) are the gold standard for detecting bacteremia, the utility of BCs in patients with community-acquired pneumonia (CAP) is controversial. This study describes the proportion of patients with CAP and afebrile bacteremia and identifies the clinical characteristics predicting the necessity for BCs in afebrile patients. METHODS Bacteremia rates were determined in 4349 CAP patients enrolled in the multi-national cohort study CAPNETZ and stratified by presence of fever at first patient contact. Independent predictors of bacteremia in afebrile patients were determined retrospectively using logistic regression analysis. RESULTS Bacteremic pneumonia was present in 190 of 2116 (8.9%) febrile patients, 101 of 2149 (4.7%) afebrile patients and 1 of 23 (4.3%) hypothermic patients. Bacteremia rates increased with the CURB-65 score from 3.5% in patients with CURB-65 score of 0 to 17.1% in patients with CURB-65 score of 4. Patients with afebrile bacteremia exhibited the highest 28-day mortality rate (9.9%). Positive pneumococcal urinary antigen test (adjusted odds ratio (AOR) 4.6, 95% confidence interval (CI) 2.6-8.2), C-reactive protein >200 mg/l (AOR 3.1, 95% CI 1.9-5.2) and blood urea nitrogen (BUN) ≥30 mg/dl (AOR 3.1, 95% CI 1.9-5.3) were independent positive predictors and antibiotic pre-treatment (AOR 0.3, 95% confidence interval 0.1-0.6) was an independent negative predictor of bacteremia in afebrile patients. CONCLUSIONS A relevant proportion of patients with bacteremic CAP was afebrile. These patients had an increased mortality rate compared to patients with febrile bacteremia or non-bacteremic pneumonia. Therefore, the relevance of fever as an indicator for BC necessity merits reconsideration.