[Ability of midregional proadrenomedullin (MR-proADM) to predict poor clinical outcome and stratify prognosis in adult patients seen for suspected infection in the Emergency Department].

Objectives: To analyze and compare the accuracy of midregional proadrenomedullin (MR-proADM) to predict poor clinical outcome (understood as progression to septic shock or admission to the Critical Care Unit -CCU-) and 30-day mortality in adult patients seen for suspected infection in the Emergency Department (ED). We also compared their performance with other biomarkers (C-reactive protein -CRP-, procalcitonin -PCT-, lactate and leukocyte count) and clinical scales widely used in routine practice (qSOFA, SRIS, NEWS-2).

Methods: A prospective, observational and analytical study was carried out on adult patients who were treated in an ED with the clinical diagnosis of an infectious process. Follow-up was carried out for 30 days. The main outcome was a composite measure that included progression to septic shock or admission to the CCU and 30-day mortality. The predictive ability was analyzed with the area under the curve (AUC) of the receiver operating characteristic (ROC) and the values of sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of MR-proADM, PCR, PCT, lactate, leukocyte count and the clinical scales.

Results: 214 patients were included, of whom 31 (14.5%) fulfilled the combined variable. The mean age was 68.6 (SD 20.75) years, 55.1% (118) were men. The MR-proADM concentration achieved the best AUC-ROC of 0.920 (95% CI: 0.850-0.989) compared to the other biomarkers and clinical scales. With a cut-off point (Cp) according to the Youden index > 2.105 nmol/L, a Se: 68%, Es: 98% and NPV: 97% were obtained. The NEWS-2 scale ≥ 5 achieves an AUC-ROC of 0.733 (95% CI: 0.630-0.835) with a Se: 87%, Es: 55% and NPV: 96%. The mixed model (MR-proADM ≥2.1 nmol/l + NEWS-2 ≥5) improved the AUC-ROC to 0.849 (95% CI: 0.782-0.915) and Se: 68%, Es: 98%, PPV: 74% and NPV: 88%.

Conclusions: In adult patients attended with clinical suspicion of infection in the ED, MR-proADM presents a high ability to predict poor clinical evolution (progression to septic shock or ICU admission) and 30-day mortality and performs better than PCT, lactate, CRP, leukocyte count and the clinical scales qSOFA, SRIS, NEWS-2. The combined model (MR-proADM ≥2.1 nmol/L + NEWS-2 ≥5) improves prediction of both MR-proADM and clinical scales.