Machine learning-derived blood culture classification with both predictive and prognostic values in the intensive care unit: A retrospective cohort study

Objectives: Diagnosis and management of intensive care unit (ICU)-acquired bloodstream infections are often based on positive blood culture results. This retrospective cohort study aimed to develop a classification model using data-driven characterisation to optimise the management of intensive care patients with blood cultures.Setting, methodology/design: An unsupervised clustering model was developed based on the clinical characteristics of patients with blood cultures in the Medical Information Mart for Intensive Care (MIMIC)-IV database (n = 2451). It was tested using the data from the MIMIC-III database (n = 2047).Main outcome measures: The prognosis, blood culture outcomes, antimicrobial interventions, and trajectories of infection indicators were compared between clusters.Results: Four clusters were identified using machine learning-based k-means clustering based on data obtained 48 h before the first blood culture sampling. Cluster gamma was associated with the highest 28-day mortality rate, followed by clusters alpha, delta, and beta. Cluster gamma had a higher fungal isolation rate than cluster beta (P < 0.05). Cluster delta was associated with a higher isolation rate of Gram-negative organisms and fungi (P < 0.05). Patients in clusters gamma and delta underwent more femoral site vein catheter placements than those in cluster beta (P < 0.001, all). Patients with a duration of antibiotics treatment of 4, 6, and 7 days in clusters alpha, delta, and gamma, respectively, had the lowest 28-day mortality rate.Conclusions: Machine learning identified four clusters of intensive care patients with blood cultures, which yielded different prognoses, blood culture outcomes, and optimal duration of antibiotic treatment. Such data-driven blood culture classifications suggest further investigation should be undertaken to optimise treatment and improve care.Implications for clinical practice: Intensive care unit-acquired bloodstream infections are heterogeneous. Meaningful classifications associated with outcomes should be described. Using machine learning and cluster analysis could help in understanding heterogeneity. Data-driven blood culture classification could identify distinct physiological states and prognoses before deciding on blood culture sampling, optimise treatment, and improve care.

Automated summary

This study developed a data-driven blood culture classification model using machine learning and cluster analysis to optimize the management and treatment of ICU patients. The results showed that different blood culture clusters had different prognoses, blood culture outcomes, and suggested different durations of antibiotic treatment.