Table 2 Proposed method that could be undertaken by healthcare organizations to incorporate externalities associated with antimicrobial use

Strategy description and costs

Describe the strategy to contain antimicrobial resistance by reducing the use of antimicrobials in hospitals.

Describe all costs associated with implementing and running the program for a minimum of 2 years.

Existing Antimicrobial Stewardship programs, Pharmacy Services, Financial departments

Baseline rate of antimicrobial resistant organism

Rates of hospital-acquired, healthcare associated or community-acquired infections due to antimicrobial resistant organisms in the healthcare facility

Infection Prevention and Control

Laboratory microbiology data linked to Discharge Abstract Databases

Strategy effectiveness

Policy effectiveness would be measured by the change in the dose-response relationship (elasticity) between antimicrobial consumption and the emergence of resistance using multivariate time series analyses accounting for different factors related to transmission of the antimicrobial resistant organism.

The model coefficients would demonstrate that temporal increases/decreases in the volume of antimicrobial use are followed by temporal increases/decreases in the incidence of hospital acquired antimicrobial resistant organism.

Infection Prevention and Control

Laboratory microbiology linked to Discharge Abstract Databases Antimicrobial utilization from patient management systems or pharmacy prescribing systems

Incremental cost of Antimicrobial resistant infections

The incremental costs of infections with antimicrobial resistant organisms is required whereby systematic differences between patients with and without the infection are accounted for.

These differences can be accounted for by a particular epidemiologic study design (i.e. matching) or through statistical modeling techniques. There is a paucity of studies currently that appropriately evaluate the true incremental costs of these infections and which consider the time-varying nature of healthcare-associated infections^a

Hospital financial departments with micro-costing data on costs/charges of patients with and without infections with an antimicrobial resistant organism.

Economic evaluation of the strategy

A simple decision analytic model to compare the costs of the policy with the costs saved through reducing antimicrobial resistant organisms (the negative externality). It would evaluate the change in the dose-response relationship between antimicrobial use and antimicrobial resistance as a result of the policy. The time horizon would be a minimum of 2 years to observe changes in antimicrobial resistance rates as a result of reduced prescribing.