Antibiotic over-prescription: a challenge for the lab

The New England Journal of Medicine is one of the most prestigious medical journals—rigorously clinical, timely, and engaged with the challenges facing healthcare today. I make it part of my routine to keep up with NEJM online.

The April 11 issue had an article, or more precisely a letter, that particularly got my attention. Headed “U.S. Outpatient Antibiotic Prescribing, 2010” it is signed by Lauri A. Hicks, DO, and Thomas J. Taylor, Jr., MS, of the Centers for Disease Control and Prevention, and Robert J. Hunkler of IMS Health in Plymouth Meeting, PA.  It tells readers of NEJM about a study the writers made of patterns of antibiotic prescribing in the United States in the most recent year for which data is available.

The authors explain the source of the information they analyzed and their methodology: “Data on oral antibiotic prescriptions dispensed during 2010 in the United States were extracted from the IMS Health Xponent database, which represents a 100% projection of prescription activity on the basis of a sample of more than 70% of U.S. prescriptions….The numbers of prescriptions and census denominators were used to calculate prescribing rates.”¹

Some numbers collated by the authors are very disturbing. In 2010, 258 million antibiotic prescriptions were written in the United States; that works out to 833 per 1,000 Americans, or five antibiotic prescriptions for every six people in the U.S. Azithromycin was the drug most often prescribed. Not surprisingly, the age groups that received the most prescriptions were under 10 years of age and over 65.

In addition, there were significant regional and state-by-state differences—ranging from 639 prescriptions per 1,000 persons in the West to 936 per 1,000 in the South. In some states, the prescription rates exceeded one per person. Even in the states with the lowest rates, they exceeded one per two persons. This is represented in a useful map, “Antibiotic Prescriptions per 1,000 Persons of All Ages According to State, 2010,” labeled as Figure 1 in Reference 1 below.

Obviously, Americans are asking for—and getting—prescriptions for antibiotics in very high numbers. No doubt, most of them are appropriate; antibiotics remain a crucial tool in treatment and patient management. But, as the authors of the letter to NEJM assert, “antibiotic use is an important factor in the spread of antibiotic resistance.” The two articles in this month’s Education section of MLO underscore the point.

In “Carbapenem-resistant Enterobacteriaceae: what has happened, and what is being done” Patrick R. Murray, PhD, explains that “carbapenem overutilization was instrumental in selecting the next generation of resistant gram-negative bacteria.” He continues: “Fewer than 15 years ago the isolation of carbapenem-resistant Enterobacteriaceae (CRE) was almost certainly the result of testing errors. Unfortunately, these resistant organisms are now established in many hospitals worldwide.” Murray considers the best ways to control CRE in hospital settings, and the role of carbapenemase multiplex assays in confirming carbapenem resistance.

In “Clostridium difficile infection: the importance of accurate diagnosis”, Paul D. Olivo, MD, PhD, and Tamara A. Ranalli, PhD, assert that “broad-spectrum antibiotic treatment can lead to diarrhea,” and that Clostridium difficile is the most common cause of antibiotic-associated diarrhea, and then discuss the diagnostic alternatives, including molecular assays, to detect C.diff.

What can you add to the conversation? Please share with MLO how antibiotic resistance linked to over-prescription has affected the work of your lab, the assays you employ to serve your institution and the healthcare needs of its patients, and your planning for the future. It’s a future that, as the letter to the NEJM and the Education articles in MLO suggest, seems to be here.