ARMD-Predict: multi-site machine learning to predict antibiotic resistance before culture results

arXiv:2610.32998v1 Announce Type: cross Abstract: Clinicians select empiric antibiotics before culture susceptibility results are available. Electronic health record (EHR) models could inform that choice, but most are developed at a single hospital and transport poorly to others. We developed ARMD-Predict using 7.5 million culture-antibiotic observations from four academic medical centers. One set of models estimates susceptibility to individual antibiotics; a second, hierarchical set predicts the infecting organism and then organism-specific resistance phenotypes. Across 23 pooled susceptibility models evaluated in same-period, patient-grouped test partitions, median area under the receiver operating characteristic curve (AUROC) was 0.77 for inpatient urine and 0.70 for inpatient blood cultures; chronological retraining reduced AUROC by approximately 0.04. At an exploratory threshold with 95% positive predictive value, derived and evaluated on the same test observations, the model identified 55% of ceftriaxone-susceptible inpatient urine observations as suitable for narrower therapy and flagged 60% of ceftriaxone-resistant observations for broader coverage. Organism classifiers achieved top-3 accuracy of 51.3-83.3%; phenotype AUROCs were conditional on the observed organism. Research applications are available at https://armd-predict.stanford.edu. Independent calibration, threshold and end-to-end prospective validation are required before clinical use.