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

Abstract

Background. 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.