Machine learning-based prediction of mortality and multidrug-resistant infection risks in ICU patients with suspected infection: a prospective national multicenter cohort study

Suspected infection can progress to sepsis or septic shock, contributing to a high mortality rate among patients admitted to ICU. However, the characteristics of suspected infection remain incompletely defined. We aimed to develop and validate predictive models to identify independent risk factors for mortality and multidrug-resistant infection in patients with suspected infection upon ICU admission in mainland China. We prospectively collected medical data from patients with suspected infection admitted to ICUs across mainland China between July 2021 and December 2022. Patients were randomly allocated to a training cohort and a validation cohort at a 7:3 ratio. Using machine learning algorithms, we identified risk factors and constructed predictive models for mortality and multidrug-resistant infection. The performance of models developed by logistic regression, random forest, extreme gradient boosting, and gradient boosting machine was evaluated using the area under the curve (AUC), Brier score, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), the Youden index, net reclassification improvement (NRI), and integrated discrimination improvement (IDI). A total of 2963 patients from 67 hospitals in mainland China were enrolled. The most common infection sites were the lung (79.28%), bloodstream (17.11%) and abdomen (16.54%). The overall mortality rate was 10.90%. The logistic regression model demonstrated the best performance for mortality prediction (AUC 0.87) and identified the following risk factors: surgery (2.39, 95CI% 1.60–3.56, p < 0.01), APACHE II score (1.51, 95CI% 1.44–1.58, p < 0.01), and bloodstream infection (2.08, 95CI% 1.40–3.10, p < 0.01) were independent risk factors of mortality. For multidrug resistant infection prediction, the logistic regression model also showed the highest discriminative ability (AUC 0.86). Independent risk factors included APACHE II score (1.06, 95%CI 1.03–1.1, p < 0.01), bloodstream infection (1.82, 95%CI 1.26–2.61, p < 0.01), urinary infection (3.42, 95%CI 2.20–5.30, p < 0.01), Klebsiella pneumoniae (11.67, 95%CI 7.91–17.21, p < 0.01), Acinetobacter baumannii (85.22, 95%CI 50.03-145.18, p < 0.01), and Enterococcus faecium (22.10, 95%CI 8.58–56.93, p < 0.01). Pneumonia was the most common infection among ICU patients in mainland China. Using machine learning techniques, we developed and validated predictive models that identified independent risk factors for mortality and multidrug-resistant infection upon ICU admission. The trial protocol was registered at ClinicalTrials.gov (Identifier: NCT04966390, Registration Date: July 14, 2021). The full record can be accessed at: https://clinicaltrials.gov/show/NCT04966390.