CERGAS Seminar "The excess burden of antibiotic-resistant bloodstream infections among hospital patients: evidence from a retrospective cohort study in Chile and potential cost-effective strategies."

Antibiotic-resistant bloodstream infections (ARB-BSIs) represent a major public health and economic challenge in Latin America. We conducted a retrospective cohort study across three tertiary hospitals in Chile (2018–2022) to quantify the excess health and economic burden of ARB-BSIs and evaluate the cost-effectiveness of targeted control strategies using deterministic compartmental modelling. The analysis included 1,218 adult patients (1,349 BSI episodes), of which 47.3% were antibiotic-resistant. The predominant resistant pathogens were Staphylococcus aureus (33% methicillin-resistant [MRSA]), Enterobacterales (50% carbapenem-resistant [CRE]), and Pseudomonas aeruginosa (65% carbapenem-resistant [CRPA]); 80% of infections were hospital-acquired. Adjusted models using inverse-probability weighting indicated that ARB-BSIs were associated with longer hospital stays (IRR=1.14, 95%CI 1.05–1.24), greater ICU admission risk (OR=1.25, 1.07–1.46), and higher mortality (OR=1.42, 1.20–1.68). Mortality hazards were particularly elevated for hospital-acquired MRSA and CRE (1.37-fold and 1.48-fold higher, respectively). ARB-BSIs incurred an excess cost of US$10,313 per patient, equivalent to 2,270 DALYs and US$53 million in annual national losses.
A sex-stratified sub-analysis (n=873) revealed that women had lower odds of acquiring CRE (OR=0.44, 0.28–0.70; p=0.0013) and MRSA (OR=0.73, 0.48–1.01; p=0.050) than men, yet higher mortality once infected. Deterministic compartmental transmission models evaluating nine interventions showed that pre-emptive isolation of high-risk male admissions was the most cost-effective strategy (ICER=US$1366/QALY and US$1083/QALY for CRE and MRSA, respectively), followed by chromogenic agar screening with MRSA decolonisation (US$2099/QALY). Probabilistic sensitivity analyses confirmed ICERs below Chile’s willingness-to-pay threshold in >80% of simulations. National implementation at 20% hospital coverage could avert substantial mortality and yield savings exceeding US$12 million.
These findings highlight the substantial excess burden of ARB-BSIs in Chile and demonstrate that targeted, cost-effective infection control, particularly focusing on high-risk male carriers, could reduce both transmission and the disproportionate mortality burden borne by women.

Speaker:

Kasim is a Research Associate at the University of Oxford since early 2024. He is part of the Nuffield Department of Primary Care Health Sciences ‘NDPCHS’ and he specialises in epidemiological, mathematical, and health-economic modelling of antimicrobial resistance (AMR). He is part of the Health Economics and Policy Unit within the NDPCHS. Kasim’s focuses on integrating transmission modelling into health-economic evaluations to enhance surveillance and intervention strategies for AMR control. Before joining the University of Oxford, Kasim worked for different organisations including the London School of Hygiene and Tropical Medicine, University College London, World Health Organisation, United Nations, among others. Kasim is affiliated with Kellogg College at the University of Oxford, reflecting its strong engagement in global health research and interdisciplinary collaboration.
Website: https://www.phc.ox.ac.uk/team/kasim-allel-henriquez / https://www.kellogg.ox.ac.uk/our-people/kasim-allel-henriquez/

Link zoom:

https://unibocconi-it.zoom.us/j/98439009149?pwd=HGQl4r91N3Eb2ZTxztblNmHbObyl8g.1

Meeting ID:

984 3900 9149

Passcode:

163940

Lunch at the end of the meeting: for those willing to participate in person, click here before the 19th of November.