How much antibiotic use is too much?

Guest author – Elizabeth Dodds Ashley, PharmD, MHS, FCCP, BCPS
Associate Director of Clinical Pharmacy Services and Antimicrobial Stewardship Pharmacist – University of Rochester Medical Center, Rochester, NY

Although this question sounds simple on the surface, answering it is one of the biggest challenges to stewardship programs both old and new.  Unlike our infection prevention colleagues, antimicrobial stewards lack a uniform tool to measure and report antimicrobial utilization in a consistent way that facilitates benchmarking with similar institutions. Knowing how utilization compares with other centers is an invaluable tool in a field such as antimicrobial stewardship where utilization is driven by trends in resistance and changed by emerging infections making goal utilization an ever moving target.

There are many variables in measuring antimicrobial use starting with the metric selected.  Limitations and difficulties with each of the options have caused many stewardship programs to develop their own tracking measures or modify the more widely accepted measures to meet the needs of a given institution, health system or purchasing group.  To add to the complexity, the data source used can greatly influence estimates of consumption.  For example, purchasing data is easy to obtain but does not necessarily reflect drug administered, whereas patient-specific data is more precise but can be labor intensive without complete electronic records.  These factors combine to create data sets that are not uniform and cannot easily be compared among institutions, making it impossible to gauge how use at one facility compares with another facility.

In early 2011, CDC’s National Healthcare Safety Network (NHSN) will re-launch the Antimicrobial Use and Resistance (AUR) Pharmacy Option to collect data on antimicrobial utilization.  In its revised format, antimicrobial days will be the measure that has been selected and where possible, this will be captured from electronic administration data.  Similar to NHSN reports on healthcare-associated infections, utilization will be normalized to level of care as well as a measure of patient days for the institution. The key to success of this initiative is participation from programs and providers actively practicing antimicrobial stewardship. This must include both support and advocacy for the utilization of electronic medical administration records to both improve efficacy of patient care and reporting of summary data for stewardship purposes, and using these data to drive local action. The launching of this reporting infrastructure that relies on submission of electronically derived summary antimicrobial use measures is a significant step forward for the field of antimicrobial stewardship which will be sustainable and provide actionable data.  While it may not fully answer the question of appropriate utilization, it will allow programs to begin comparing antibiotic use on a level playing field.

Elizabeth S. Dodds Ashley, PharmD, is currently the Associate Director for Clinical Pharmacy Services and an Infectious Diseases pharmacist at the University of Rochester Medical Center in Rochester, NY.  In addition, she has appointments as Adjunct Assistant Professor in the Department of Medicine, Division of Infectious Disease and International Health at Duke University School of Medicine, Durham, NC and Instructor of Medicine in the School of Medicine and Dentistry at the University of Rochester, Rochester, NY.

Dr. Dodds Ashley received her Doctor of Pharmacy degree from the Bouvé College of Pharmacy and Health Sciences at Northeastern University, Boston, Massachusetts in 1998.  She subsequently completed her pharmacy practice residency at Duke University Health System and a specialty residency in adult internal medicine/infectious disease with Duke University Health System and Campbell University before joining the Department of Medicine at Duke University Medical Center in 2000.  While at Duke, she served as the clinical pharmacist for the Infectious Diseases Transplant Consult Service and Co-Chair of the Antibiotic Evaluation Team as well as a Clinical Assistant Professor of Pharmacy Practice at the Campbell University School of Pharmacy.  Additionally, she completed her Masters in Health Science in Clinical Research at Duke University School of Medicine in 2006.  In April 2008, Dr. Dodds Ashley joined the University of Rochester Medical Center as a Clinical Pharmacy Specialist in Infectious Diseases until transitioning to her current role in September 2009.

Her clinical, teaching, and research activities focus on antimicrobial stewardship and infectious diseases in the transplant population. Recent areas of research include pharmacokinetics of antifungal agents and preventative strategies for invasive fungal infections in solid-organ and bone marrow transplant recipients.. Dr Dodds Ashley has coauthored abstracts, book chapters, and journal articles, and she has given presentations at seminars, grand rounds, and regional and national professional meetings. Among the journals her articles have appeared in are Journal of Microbiology, Expert Review of Anti-Infective Therapies, Clinical Infectious Diseases, Pharmacotherapy, and Current Opinion in Pharmacotherapy.  Her professional affiliations include American College of Clinical Pharmacy where she served as the 2009-2010 Chair of the Infectious Diseases Practice and Research Network and the Society of Infectious Disease Pharmacists, participating on the strategic planning committee in 2007-2008.