In the hospital antimicrobial stewardship programs, most return on investment is a combination of the extent to which antimicrobial costs are saved through the programs that are implemented and the projected costs in the prevention of driving resistance and in the increasing adverse event rates associated with these antibiotics, as well as all the other downstream impacts that happen when there's overuse of antimicrobials.
At a human-scale level, an antimicrobial stewardship program in the hospital, when compared to the animal scale in terms of quantity—grams—of antimicrobials, is significantly less. However, the return on investment economically is measured in ways that focus on how we reduce antimicrobial overuse in the health care system, in hospital systems, and also how that will result in reduction of adverse events related to antimicrobials.
Adverse events, when we think of antibiotics, are not just antimicrobial resistance. They're all the things that drive medication consequences. We know that the class of antibiotics, when compared to other classes of medications, is often the number two or number three driver of medication adverse events. Therefore, the measure of return on investment has to be broader in scale and not just focused on the costs of procurement or the cost of the use of antibiotics itself.
