1895. Serious Antibiotic-Related Adverse Effects Following Unnecessary Dental Prophylaxis in the United States

Background Dentists prescribe 10% of outpatient antibiotics in the United States, with a significant portion of these being for prophylaxis. We previously found that 80% of prescriptions for prophylaxis prescribed prior to dental visits are unnecessary; however, the sequelae of these unnecessary antibiotics have not been characterized. Our objective was to assess the harms of unnecessary antibiotic prophylaxis using Truven, a national health claims database. Methods This was a retrospective cohort study of patients with dental visits from 2011 to 2015 linked to medical and prescription claims. Patients with commercial dental insurance without a hospitalization or extra-oral infection 14 days prior to antibiotic prophylaxis (≤2 days supply dispensed within 7 days before a dental visit) were assessed for inclusion. Patients with unnecessary antibiotic prophylaxis (defined as antibiotic prophylaxis in patients who both did not undergo a procedure that manipulated the gingiva/tooth periapex and did not have an appropriate cardiac diagnosis) were included and assessed for serious antibiotic-related adverse effects (AAE). The primary endpoint was the cumulative incidence of any AAE within 14 days post-prescription (composite of allergy, anaphylaxis, C. difficile infection, or ED visit). The secondary analyses were the cumulative incidence of each individual AAE and the risk difference of the primary endpoint between amoxicillin and clindamycin. Results Of the 168,420 dental visits with antibiotic prophylaxis, 136,177 (80%) were unnecessary and included for analysis. 3.8% of unnecessary prescriptions were associated with an AAE; primary and secondary endpoints are listed in the Table. ED visits (1.2%) and new allergies (2.9%) were most frequent. Clindamycin was associated with more AAE than amoxicillin (risk difference 322.1 per 1000 person-years, 95% CI: 238.5 - 405.8). Conclusion Even though antibiotic prophylaxis is prescribed for a short duration (≤2 days), it is not without risk. Since most AAE are diagnosed in medical settings, dentists may not be aware of these adverse effects. These data provide further impetus to decrease unnecessary prescribing of antibiotic prophylaxis prior to dental procedures. Disclosures All Authors: No reported Disclosures.