Antibiotic Prescribing Varies Greatly Among Family Physicians in Canada

Antibiotic prescribing varies greatly among family physicians, and the differences aren’t explained by patient characterizations, according to a recent study in Canada.

The 5-year cohort study, published in the Journal of Antimicrobial Chemotherapy, examined nearly 4 million patient visits involving more than 300,000 patients and more than 300 family physicians.

The study found a median of 54 antibiotics prescribed per 1000 visits, with female patients between the ages of 3 and 5 being the most likely to receive antibiotics compared with men aged 65 and older, according to the study.

“The biggest surprise was that patient characteristics explained none of the interphysician variability,” corresponding author Kevin Schwartz, MD, MSc, FRCPC, DTM&H, told Contagion^®. “We found that after adjusting for all patient characteristics the odds of a patient receiving an antibiotic, on average, varied by 1.7 times simply by virtue of the physician they saw. This is a remarkable amount of variation that seems to be completely driven by the physician themselves and not the type of patients that they see.”

Schwartz is an IPAC physician affiliated with Public Health Ontario, an infectious disease consultant at St. Joseph’s Health Centre, an adjunct scientist at ICES (formerly the Institute for Clinical Evaluative Sciences), and assistant professor at the Dalla Lana School of Public Health at the University of Toronto.

Antibiotic-resistant infections affect more than 2 million people, killing at least 23,000 each year, according to the US Centers for Disease Control and Prevention. Over-prescribing of drugs has been blamed for the rise in antibiotic-resistant infections, yet reducing prescriptions has been difficult, with many physicians succumbing to pressure from patients and families for medicine, according to a study reported last year. Rates of antibiotic prescriptions fell by only 5% from 2011 to 2016 in the United States, according to a recent study.

The study in Canada used multilevel regression modeling to identify predictors associated with antibiotic prescribing such as patient age and sex, comorbidities, socioeconomic status, how busy the physician’s practice is, and geographical location.

“The large amount of interphysician variability in antibiotic prescribing, that is not explained by differences in patient populations, suggests there is room to align prescribing practices and reduce overall antibiotic use,” Schwartz told Contagion^®. “Over 90% of antibiotics are used outside of hospitals, and most by family physicians. We need a better understanding where there is inappropriate use and innovative ways of effectively conducting antimicrobial stewardship in primary care to safely reduce unnecessary antibiotics and slow the emergence of antimicrobial resistance.”

The study found challenges to stewardship programs, including limited administrative oversight, difficulty accurately measuring antibiotic use, and emotionally salient factors such as perceived patient expectations and fear of clinical decline of patients. It pointed to multifaceted interventions, including public and provider education and peer comparison feedback.

“We have a program of research titled OPTIMISE or The Ontario Program To Improve AntiMIcrobial USE. Through this program of research, we hope to develop a better understanding of how antibiotics are used in the community, the degree of inappropriate use, and the impact of inappropriate use to the health of patients,” Schwartz told Contagion^®. “The ultimate goal of our program is to improve the quality of care patients are receiving through reducing unnecessary antibiotics. We are currently engaged in a study of providing peer-comparison feedback to Ontario primary care physicians on their antibiotic prescribing volume. In December 2018 we mailed 3000 letters to the highest antibiotic prescribing primary care physicians in the province. We will be evaluating the impact of these letters in a randomized controlled trial design to study optimal ways of providing feedback to physicians to reduce unnecessary antibiotic use.”