“Dear Dr" Letter Reduces Length and Cost of Antibiotic Treatment

A letter sent to primary care physicians (PCPs) in the highest 25th percentile of their peers in quantity or duration of antibiotic prescriptions resulted in modest reduction in duration and costs of drug treatment, but with less impact on the high number of prescriptions.

"Peer-comparison audit and feedback can be an effective tool to modify PCP behavior and improve patient outcomes," observed Kevin Schwartz, MD, Public Health Ontario, Toronto, Ontario Canada, and colleagues.

Schwartz and colleagues note that high and/or inappropriate use of antibiotics is associated with increases in patient- and ecological-level drug resistance, adverse drug effects, antibiotic drug costs; and can be driven, in part, by patients' expectations and their seeking health care for self-limited illnesses.

The investigators tested the letter as social normative feedback in a randomized controlled trial to determine whether it could influence antibiotic prescribing patterns of PCPs who, they point out, are "crucial stakeholders and partners in antimicrobial stewardship efforts."

Schwartz and colleagues accessed centralized medication records of the Ontario province of Canada to rank family physicians and general practitioners by total number of antibiotic prescriptions, and the number of prescriptions in excess of 7 days duration provided during the period of March 1, 2017 to February 28, 2018.

The physicians ranked in the highest 25th percentile in total quantity of antibiotic prescriptions, or in prescriptions for amounts in excess of 7 days received letters indicating their ranking and describing guidelines for initiating antibiotic treatment, and/or of appropriate duration. The guidelines were drawn from recommendations and tools of the Choosing Wisely Canada resources.

The letter was formulated in an iterative process for stakeholder engagement; with text developed in association with the Ontario Medical Association Section on General and Family Practice and cosigned by the Chair of the Section, and the Chief of Infection Prevention and Control at Public Health Ontario.

A total of 1484 PCPs received the letter on initiating antibiotic treatment, 1486 received the letter on optimal duration of treatment, and 496 serving as controls did not receive a letter.Prescribing was monitored for 12 months after the letter was sent.

Schwartz and colleagues reported that receipt of the initiation letter had no statistically significant effect compared to controls; but there was a statistically significant difference between the duration letter group and the initiation letter group on prolonged duration prescriptions.The initiation letter resulted in a 4.2% relative difference in overall ambulatory antibiotic prescribing.

The letter focusing on appropriate duration, however, resulted in a relative 8.1% fewer prolonged-duration prescriptions, with a corresponding 6.1% relative reduction in antibiotic drug costs.The investigators calculated that the duration letter resulted in an average of 24 fewer prolonged-duration and $771 in drug costs savings per PCP over 12 months.

The investigators characterized the intervention for high quantity prescribing as only "modestly effective at reducing antibiotic use".Further, they attributed the relative success of the duration letter to those performing most poorly at baseline, more likely to be in the later part of their career (≥25 years after medical graduation).

"In the present trial, we demonstrated that these same PCPs were considerably more likely to change their behavior in response to feedback," Schwartz and colleagues indicated.

In regard to the effectiveness of the single letter, the investigators acknowledge that "more marked reduction in appropriate antibiotic prescribing will require additional strategies."