Chicago—With as many as one in 10 antibiotic prescriptions prescribed by dentists, pharmacists fill a lot of scripts from that source. So, they might be surprised that the vast majority of those drugs might be unnecessary.

A study published in JAMA Network Open argues that 81% of antibiotics prescribed by dentists likely had no benefit. The highest rates were documented in the western United States.

A possible explanation, according to University of Illinois Chicago–led researchers, is that prior infection prophylaxis guidelines recommended that patients with recent prosthetic joint implants receive antibiotic prophylaxis before a dentist visit because of concerns about infective endocarditis and prosthetic joint infections secondary to bacteremia introduced during dental care. Those guidelines were revised in 2007 and 2013, however, and now antibiotics before dental procedures are only recommended per guidelines in patients with cardiac conditions at the highest risk of adverse outcome from infective endocarditis undergoing invasive dental procedures, according to background information in the article.

The study used Truven, a national integrated health-claims database, for the retrospective cohort study. Dental visits from 2011 to 2015 were linked to medical and prescription claims from 2009 to 2015, with analysis from August 2018 to January 2019. Included in the research were more than 90,000 U.S. patients with commercial dental insurance without a hospitalization or extraoral infection 14 days before antibiotic prophylaxis—defined as a prescription with 2 or fewer days’ supply dispensed within 7 days before a dental visit.

Specifically, the study looked at the presence or absence of cardiac diagnoses and dental procedures that manipulated the gingiva or tooth periapex.

The study determined that, from 2011 to 2015, antibiotic prophylaxis was prescribed for 168,420 dental visits for 91,438 patients with a median age of 63 years. Researchers point out that in 90.7% of dental visits, a procedure was performed that would necessitate antibiotic prophylaxis in high-risk cardiac patients, with prevalent comorbidities including prosthetic joint devices (42.5%) and cardiac conditions at the highest risk of adverse outcome from infective endocarditis (20.9%).

Based on the guidelines, the study team calculated that 80.9% of antibiotic prophylaxis prescriptions before dental visits were unnecessary. Clindamycin was more likely to be unnecessary relative to amoxicillin (odds ratio [OR], 1.10; 95% CI, 1.05-1.15), the study noted.

Factors most often associated with unnecessary antibiotic prophylaxis, according to the report, were:
• Prosthetic joint devices (OR, 2.31; 95% CI, 2.22-2.41),
• Tooth implant procedures (OR, 1.66; 95% CI, 1.45-1.89),
• Female sex (OR, 1.21; 95% CI, 1.17-1.25), and
• Visits occurring in the western U.S. (OR, 1.15; 95% CI, 1.06-1.25).

“More than 80% of antibiotics prescribed for infection prophylaxis before dental visits were unnecessary,” study authors conclude. “Implementation of antimicrobial stewardship in dental practices is an opportunity to improve antibiotic prescribing for infection prophylaxis.”

“Use of preventive antibiotics in these patients opens them up to the risks associated with antibiotic use—increasing bacterial resistance and infections, for example—when the evidence used to develop the guidelines suggests that the risks outweigh the benefits in most patients,” said Katie Suda, PharmD, MS, the corresponding author on the study.

“Dental providers are very thoughtful when they develop care plans for their patients and there are many factors that inform dentists’ recommendations and the medications they prescribe, but this study shows that there is an opportunity for dentists to reevaluate if necessary and incorporate renewed commitments to antibiotic stewardship into their practices that limit preventive prescriptions to a small group of patients,” added Susan Rowan, DDS, executive associate dean and associate dean for clinical affairs at the UIC College of Dentistry.

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