OBJECTIVES: Antimicrobial resistance (AMR) is a global public health concern that can lead to increased morbidity and mortality. Patients with antimicrobial-resistant infections typically require longer hospital admissions, which may impact other health services. We estimated the additional bed day costs associated with treating resistant relative to susceptible infections in Ireland.

METHODS: A simulation model was developed to estimate the cost due to excess length-of-stay of treating 16 common antibiotic-resistance bacterium combinations. Infections were classified as either bloodstream, respiratory, urinary tract, surgical site or ‘other’ infections. The incidence of resistant infections was based on European Antimicrobial Resistance Surveillance Network data, collected from all public acute hospitals in Ireland in 2019. Attributable length-of-stay data were sourced from the literature. The national average cost of an inpatient bed day was applied. Intensive care bed-day costs were considered in scenario analysis.

RESULTS: The estimated additional cost of AMR due to excess length-of-stay was €12,020,068 (95% CI: €4,879,603-€23,267,352). Resistant ‘other infections’ accounted for 36.7% of costs, followed by resistant surgical site (25.0%), bloodstream (18.7%), respiratory (10.6%) and urinary tract (9.0%) infections. When intensive care costs were applied for cases potentially admitted to intensive care (based on a weighted probability of admission for infection type), the estimated additional cost was €15,515,044 (95% CI: €6,594,222-€28,723,702).

CONCLUSIONS: The estimated economic burden of AMR on public acute hospitals in Ireland due to excess length-of-stay likely exceeded €12 million in 2019. The analysis was limited to hospital costs relating to excess length-of-stay for routinely collected antibiotic-resistance bacterium combinations, so is likely to be a considerable underestimate of total costs to the health system and to the individuals affected. Nonetheless, it provides a baseline against which progress can be measured. Expanded surveillance is needed to effectively identify and manage AMR, as well as to allow broader evaluations of AMR-associated costs.