Antimicrobial stewardship: a matter of process or outcome?

The risk of antimicrobial resistance and superinfection is increasing alongside rates of hospital-acquired infection. Imprudent antibiotic use combined with few novel antimicrobials can speed resistance. Antimicrobial stewardship programs (ASPs) advocate for judicious use of available antimicrobials to preserve their usefulness. Decreased antibiotic expenditures was the backbone of early justification for ASPs, but the function of these programs has evolved into measuring the quality and appropriateness of antimicrobial use. Proper evaluation of an ASP helps to inform which methods work best for a particular institution and can help to define best practices at a more global level. Study design and duration limitations, however, can make it difficult to measure the impact of these programs. Process measures have been validated and can evaluate quality of care; however, they do not adequately describe the clinical impact of these programs at the patient level. Outcome measures also have limitations; they are not a direct measure of quality of care. Therefore, both process and outcome measures need to be defined and assessed when evaluating an ASP to confirm that goals of the intervention are attained and clinical objectives are met. Most available well-designed studies judging the effectiveness of ASPs use process measures alone. Adding improvements in clinical outcomes to process measures would theoretically attract the attention of a broader audience and provide additional support to expand current ASPs and develop novel ASPs.