2SPD-006 Budgetary impact of aztreonam shortage in the treatment of metallo-beta-lactamase-producing gram-negative bacteria

<h3>Background and Importance</h3> Metallo-beta-lactamases are the most clinically significant acquired carbapenemases due to their ability to hydrolyse β-lactam antibiotics, except aztreonam and cefiderocol. Since April 2024, due to the aztreonam shortage, the national medicines and healthcare products agency (MHPA) established strict prioritisation criteria for its use. Aztreonam can only be employed in the context of metallo-beta-lactamases when cefiderocol cannot be used. <h3>Aim and Objectives</h3> To estimate the budgetary impact of the aztreonam shortage in a medium-complexity hospital under different scenarios. <h3>Material and Methods</h3> Economic evaluation conducted in September 2024 in a medium-complexity hospital. Using electronic health records, patients infected and/or colonised with metallo-beta-lactamases treated with ceftazidime-avibactam+aztreonam (CAZAVI-AZ) between January 2019 and December 2023 were identified. The annual incidence rate was calculated, based on the hospital’s served population, along with the median treatment duration. Treatment costs were calculated using the laboratory reported selling prices (LRSP) and median treatment days. The budgetary impact (cefiderocol costs minus CAZAVI-AZ costs) was estimated for periods of 6 months, 1 year, and 2 years, comparing standard doses from the technical sheet. A sensitivity analysis was performed, considering the cost using the maximum doses of CAZAVI-AZ for this indication. <h3>Results</h3> Over 4 years, the incidence was 8.8 cases per 100,000 inhabitants annually. The median treatment duration was 6.8 days [IQI 1.5–10.4]. LRSP per vial was €161.82 for cefiderocol, €14.83 for aztreonam, and €125.42 for ceftazidime-avibactam. With standard doses, the total cost per patient was €3,163.53 for CAZAVI-AZ and €6,602.05 for cefiderocol. Assuming maximum CAZAVI-AZ doses, the total cost per patient was €3,365.22. Considering annual incidence and the hospital’s population (170,000), the budgetary impact was €24,069.64 for 6 months, €51,577.83 for 1 year, and €103,155.66 for 2 years. Sensitivity analysis showed slightly lower impact with maximum CAZAVI-AZ doses: €22,657.81 for 6 months, €48,552.45 for 1 year, and €97,104.9 for 2 years (5.87% difference). <h3>Conclusion and Relevance</h3> The aztreonam shortage and high cefiderocol cost will significantly impact the treatment budget for metallo-beta-lactamase-producing gram-negative bacterial infections. The estimated annual impact was €51,577.83, emphasising the importance of ensuring aztreonam supply and managing shortages effectively. Beyond the economic impact, it is crucial to assess the ecological consequences of the MHPA’s strategy. <h3>References and/or Acknowledgements</h3> <h3>Conflict of Interest</h3> No conflict of interest