The IDSA drafts guidelines for antimicrobial stewardship

December 2005

A committee formed by the IDSA has written guidelines for antimicrobial stewardship, and Timothy H. Dellit, MD, presented a draft of the guidelines at the 43^rd Annual Meeting of the Infectious Diseases Society of America, held in San Francisco.

The IDSA Guidelines for Antimicrobial Stewardship are still in draft form and will undergo additional review prior to final approval and distribution.

Dellit noted that antimicrobial stewardship is important because antimicrobials account for more than 30% of hospital formulary budgets. Additionally, approximately 50% of antimicrobial use is thought to be inappropriate, and resistance rates are increasing in both inpatient and outpatient settings.

“Once antimicrobial resistance emerges, it can have a significant impact on the care of our patients, and it also leads to increased cost of care,” said Dellit, who is assistant professor of medicine in the division of allergy and infectious diseases at the University of Washington in Seattle.

The primary goal of the guidelines is to optimize clinical outcomes while minimizing unintended consequences, such as drug-drug interactions, the emergence of resistance and the emergence of Clostridium difficile. A secondary goal is to reduce health care costs without adversely affecting quality of care.

“The hope with these guidelines is to foster the development of comprehensive evidence-based programs, recognizing that they must be individualized within a given institution based on local antimicrobial use and resistance patterns, as well as recognizing that they are dependent on available resources that may differ depending on the size of the institution or clinical setting,” he said.

However, hospital administrators need to understand that these programs are financially self-supporting. They typically result in a 20% to 30% decrease in antimicrobial use, and annual savings of more than $200,000 to $900,000 per year have been reported in the literature.

“These programs should be developed with the support of hospital administrators and in collaboration with local providers under the auspice of quality assurance and patient safety,” he explained.

Formulary restriction

There are two primary active strategies of antimicrobial stewardship, and they are not mutually exclusive. One is prospective audit and intervention with direct feedback to the prescriber, and the second is formulary restriction and pre-authorization.

Formulary restriction and pre-authorization can have a significant upfront effect in decreasing antimicrobial use and cost, and it has been useful in certain outbreak settings, such as the restriction of clindamycin to stop nosocomial C. difficile outbreaks. However, the long-term effect on resistance is not clear. In fact, in some cases, it may simply shift use and resistance in an unintended direction. Programs that use pre-authorization to improve antimicrobial stewardship must monitor overall trends in antimicrobial use to respond to such shifts in use.

“These two active processes can then be supplemented by the following: education, guidelines and clinical pathways,” Dellit said.

Additional elements that should be considered include streamlining therapy based on culture results and antimicrobial order forms, as well as parenteral-to-oral conversion when appropriate. “This can have a significant impact on length of stay and costs for the institution,” he added.

Currently, there are insufficient data to recommend antimicrobial cycling. “In fact, mathematical models that have looked at this have suggested that heterogeneous antimicrobial use may be more appropriate in terms of decreasing the emergence of resistance,” he said.

Antimicrobial stewardship programs can facilitate multidisciplinary development of evidence-based practice guidelines incorporating local microbiology and resistance patterns.

Dellit used hospital-acquired pneumonia and ventilator-associated pneumonia as examples to highlight a number of important stewardship principles because these entities are responsible for 50% of all antimicrobial use within the ICU. These types of pneumonia highlight the importance of adequate upfront therapy to decrease mortality, the role of diagnostic strategies, the influence the strategies can have on antimicrobial therapy, the importance when selecting empiric therapy to perform a risk factor assessment for multidrug-resistant pathogens and early onset vs. late onset depending on the number of days on mechanical ventilation and length of the hospital stay.

Combination therapy may have a role in upfront therapy in critically ill ICU patients, he explained, although it is not recommended to prevent the emergence of resistance.

Program partners

Another key recommendation is a move toward automated systems in order to generate targeted interventions. “In a simplistic way, it would be ideal to have a local programmer who could generate a list of the interventions to help guide the pharmacist and infectious disease physician. It is my hope that electronic medical records and computer physician order entry continue to evolve and improve, and that we may be able to tie in principles of stewardship within the decision-making process,” he said.

The clinical microbiology laboratory is an important partner with an antimicrobial stewardship program, Dellit explained, because the lab provides patient-specific culture and susceptibility data, and assists in infection control and surveillance of resistant organisms and investigation of outbreaks.

“When one is developing these programs, one really needs to establish process and outcome measures as priorities to determine the local impact,” he said. “This will be very important so you know how to switch and change interventions depending on shifts in usage and resistance, and also so you can report back to hospital administration.”

For more information:

• Dellit TH. Antimicrobial stewardship in Healthcare. Symposium #67. Presented at the 43^rd Annual Meeting of the Infectious Diseases Society of America. Oct. 6-9, 2005. San Francisco.