Carbapenem-resistant Acinetobacter baumannii bloodstream infections in critically ill patients: prognostic factors and development of a nomogram

TL;DR

This study identifies key risk factors for death in ICU patients with CRAB bloodstream infections and creates a predictive model to help guide treatment decisions.

Contribution

A novel nomogram model is developed to predict 30-day mortality in ICU patients with CRAB bloodstream infections.

Findings

30-day mortality rate among ICU patients with CRAB-BSI was 60.0%.

Age, impaired consciousness, corticosteroid use, SOFA score, and CRP level were independent risk factors for mortality.

The nomogram achieved strong predictive accuracy with an AUROC of 0.863.

Abstract

This retrospective study aimed to identify the clinical features and prognostic determinants in intensive care unit (ICU) patients with carbapenem-resistant Acinetobacter baumannii (CRAB) bloodstream infection (BSI) and to establish a personalized risk prediction model.

This retrospective cohort study included 185 ICU patients with CRAB-BSI at a tertiary care hospital between 2013 and 2023. Based on 30-day outcomes, patients were categorized into survival and non-survival groups. Independent risk factors for mortality were identified through univariate and multivariate logistic regression analyses. These factors were used to construct a nomogram prediction model. Model performance was evaluated by assessing discrimination using the area under the receiver operating characteristic curve with a calibration plot, and clinical utility via decision curve analysis.

The 30-day mortality rate among ICU patients with CRAB-BSI was 60.0%. Multivariate analysis revealed that age [odds ratio (OR) = 1.04, 95% confidence interval (CI): 1.02–1.07], impaired consciousness (OR = 5.10, 95% CI: 2.27–11.45), prior corticosteroid use (OR = 5.82, 95% CI: 2.10–16.12), Sequential Organ Failure Assessment (SOFA) score (OR = 1.26, 95% CI: 1.12–1.42), and C-reactive protein (CRP) level (OR = 1.01, 95% CI: 1.01–1.02) were independent risk factors for 30-day mortality. A nomogram incorporating these variables achieved an area under the curve (AUROC) of 0.863 for predicting 30-day mortality risk. The calibration curve indicated excellent concordance between predictions and observed outcomes, and decision curve analysis demonstrated significant clinical net benefit over a wide range of probability thresholds.

Mortality is high in ICU patients with CRAB-BSI and is significantly associated with age, impaired consciousness, corticosteroid use, SOFA score, and CRP level. The developed nomogram exhibits strong predictive accuracy and may function as a practical tool for quantitative management decisions.

Figures