[Utility of the medial region of pro-adrenomodulin for the detection of true bacteremia in elderly patients treated in the emergency department for suspected infection].

Objective: The prediction of bacteremia in the emergency department (ER) is important for initial decision-making. The elderly population is a diagnosis challenge. The objective was to evaluate the accuracy of mid regional pro-adrenomedullin (MR-proADM) to identify true bacteremia (BV) in elderly patients attended in 3 hospital emergency departments.

Methods: Observational study including patients ≥75 years of age or older attended in the ER for suspected infection in whom a blood culture (BC) was extracted. Sociodemographic, comorbidity, hemodynamic and analytical variables, biomarkers [MR-proADM, procalcitonin (PCT), C-reactive protein (CRP) and lactate] and final diagnosis were collected. The primary outcome was a true positive on a blood culture.

Results: A total of 109 patients with a mean age of 83 (SD: 5.5) years were included. A final diagnosis of BV was obtained in 22 patients (20.2%). The independent variables to predict it were PCT (OR: 13.9; CI95%: 2.702-71.703; p=0.002), MR-proADM (OR: 4.081; CI95%: 1.026-16.225; p=0.046) and temperature (OR: 2.171; CI95%: 1.109-4.248; p=0.024). Considering the cut-off point for MR-proADM (2.13 mg/dl), a sensitivity (Se) of 73%, specificity (E) of 71%, a positive predictive value (PPV) of 39%, a negative predictive value (NPV) of 91%, a positive likelihood ratio (LHR+) of 2.53 and a negative likelihood ratio (LHR-) of 0.38; for PCT (0.76 mg/dl) a Se of 90%, E of 65%, PPV of 40%, NPV of 96%, LHR+ 2,64 and a LHR- of 0.14 were obtained. When combining both, a Se of 69%, E of 84%, PPV of 52%, NPV of 91%, LHR+ of 4.24 and LHR- of 0.38 were observed.

Conclusions: Elevated levels of PCT and MR-proADM were independently associated with an increased risk of BV and the combination of both improves the accuracy to identify these patients.