Dental Antibiotics Could Be Adding to C difficile Cases

Marcia Frellick

October 16, 2017

SAN DIEGO — Antibiotics prescribed by dentists could be contributing to cases of potentially deadly Clostridium difficile, according to findings presented in a press conference at IDWeek 2017.

C difficile infections are the primary cause of healthcare-associated diarrhea, and antibiotic use is one of the top risk factors. The latest numbers from the Centers for Disease Control and Prevention show there were nearly half a million C difficile infections in the United States in 2011, and 29,000 patients died within a month of diagnosis.

For the current study, Stacy Holzbauer, DVM, MPH, an epidemiology field officer for the Centers for Disease Control and Prevention and the Minnesota Department of Health, and colleagues interviewed 1626 people from five Minnesota counties diagnosed with community-acquired C difficile between 2009 and 2015. The cases were considered to be community-acquired if the patients had not had an overnight stay in the hospital in the last 12 weeks.

Of the 1626 patients, 926 (57%) reported they had been prescribed an antibiotic in the prior 12 weeks, and for 136 patients (15%), the antibiotic had been prescribed by a dentist.

However, just more than a third (34%) of those prescribed antibiotics by a dentist had no mention of the dental antibiotics in their medical chart. Dr Holzbauer presented the findings in a press conference here October 6.

Three-Way Communication Gap

Dr Holzbauer told Medscape Medical News that several things are going on: Physicians are not always asking about dental antibiotics specifically when they take a medical history, dentists are not necessarily focused on the possible harms of antibiotics and are not warning patients of the potential risks or reminding them to report the antibiotic use to their primary care physicians, and patients are not making sure all their providers know about antibiotics from different sources.

"I think the biggest issue is that dentists have been left out of the conversation, because no one really recognized how large the dental prescribing was in the greater scheme of things, especially when it comes to outpatient prescribing," she said.

There is also no feedback if a patient experiences adverse effects after taking antibiotics prescribed by their dentist. "No one goes to their dentist when they get diarrhea," she explained.

The authors found that people who were prescribed antibiotics for dental procedures tended to be older than those prescribed antibiotics for other indications (57 years old vs 45 years), and more likely to receive clindamycin, which is an antibiotic that causes diarrhea and has been more closely linked to C difficile infection compared with other antibiotics (50% vs 10%).

Dr Holzbauer noted that medical providers have been hearing cautions against using antibiotics for inappropriate indications "for at least 20 years, and they're still struggling. I think dentists are at the place primary care physicians were 20 years ago."

Previous research showed that dentists were responsible for 24 million antibiotic prescriptions in 2013 (about 10% of the total antibiotics prescribed in an outpatient setting), which Dr Holzbauer said "was shocking to everyone." Outpatient prescribing of antibiotics needs closer scrutiny, she continued, and "dentists have been a blind spot."

Dr Holzbauer said many dentists also may not be meeting current prescribing guidelines for antibiotics. Until 2015, for instance, prophylactic antibiotics were advised before dental procedures in certain cases when a patient had a prosthetic joint, such as a hip replacement.

However in 2015, the American Dental Association (ADA) issued a practice guideline that said no antibiotic prophylaxis is needed for people with joint replacements. Yet that change may not have reached all dentists, she said.

Hilary Babcock, MD, from the Washington University School of Medicine in St. Louis, Missouri, who is the Society for Healthcare Epidemiology of America vice chair of IDWeek, told Medscape Medical News that sometimes patients come in to dentists saying their surgeon told them years ago when they got their hip replacement that they would need to take antibiotics before a dental cleaning.

She said if dentists are seeing the patient once a year, they may not see the benefit in taking the time to convince patients they do not need the antibiotics. Supporting dentists with educational materials is one way to help reverse the trend, along with open discussions on what dentists see as barriers to appropriate prescribing.

Dr Babcock said she found the results of the study surprising and explained this is likely coming to light only now because of the convergence of recent increased focus on tracking the spread of C difficile and on antimicrobial stewardship.

Dentists are not the top prescribers of antibiotics in community settings, she noted, and primary care prescriptions for upper respiratory infections are still a major source.

"I just think dentists haven't been identified before," she said.

Dr Babcock said there is growing interest in using pharmacy benefit provider databases to identify antibiotic use in insured populations and to track prescribing trends.

Dr Holzbauer said they have shared the information with the Minnesota Dental Association, and the group was glad to have hard data on the potential consequences of antibiotic prescribing to help in improving communication.

Dr Holzbauer would like to see further studies determine who prescribed antibiotics to patients who then developed C difficile and to find a nonconfrontational way to deliver the feedback to the prescriber.

"We've seen in outpatient clinics that peer feedback and peer comparisons seem to be most effective in reducing inappropriate prescribing," Dr Holzbauer said.

She also noted that although the results in the five counties are likely representative of Minnesota, more research would need to be performed to determine generalizability nationally.

Dr Holzbauer and Dr Babcock have disclosed no relevant financial relationships.

IDWeek 2017: Abstract 78. Presented October 5, 2017.

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