Inappropriate antibiotic prescribing still rampant

Despite major efforts in the past three decades to decrease improper antibiotic prescribing and reduce the risk of antibiotic resistance, antibiotics are still being prescribed inappropriately in the outpatient setting. A recent BMJ article found that about 23% of antibiotics were prescribed for a diagnosis that does not warrant a prescription antibiotic.

The researchers looked at claims for antibiotics for more than 19 million children and adults. They then looked at the diagnostic claims submitted in the days before to see if those diagnostic claims, in the form of ICD-10-CM codes, either always, sometimes, or never justified an antibiotic. 

They found that of the more than 15 million antibiotics prescribed to this cohort in 2016, 23% were inappropriate ("never justify an antibiotic"), 36% were potentially appropriate ("sometimes justify an antibiotic"), and 29% were not associated with a recent diagnosis code—leaving just under 13% of antibiotics deemed appropriate ("always justify an antibiotic"). 

“The magnitude of antibiotic overuse at the population level was striking to me. Because the rate of antibiotic use was so high in our study (more than 800 prescriptions per 1,000 patients), we found that approximately one in seven patients received unnecessary antibiotic prescriptions during 2016,” said Kao-Ping Chua, MD, PhD, assistant professor of pediatrics, University of Michigan Medical School in Ann Arbor, and first author of the study. 

Inappropriate antibiotic prescriptions were most commonly prescribed for acute bronchitis, acute upper respiratory tract infections, and respiratory symptoms such as cough, and were mainly for azithromycin, amoxicillin, and amoxicillin-clavulanate. 

“This provides more of a question than an answer,” said Christopher McCoy, PharmD, BCPS, BCIDP, regarding the 29% of antibiotic prescriptions that were not associated with a diagnosis code. McCoy is associate director of antimicrobial stewardship and the infectious diseases PGY-2 residency program director at Beth Israel Deaconess Medical Center in Boston. 

There are several explanations, the authors pointed out, that could explain these missing codes. One is that the database only had access to medical claims, not dental claims, and it is possible that these prescriptions were for dental prophylaxis, which may or may not be appropriate. 

The authors also explained that many antibiotic fills were refills, meaning a diagnosis would not be found since they were not seen by a prescriber in the days before refilling the prescription. This could explain almost 17% of the fills that were not accompanied by a diagnosis code. The top three refilled antibiotics were doxycycline, minocycline, and sulfamethoxazole-trimethoprim. The first two are commonly used to treat acne. 

“A major driver [of inappropriate prescribing] is clinicians’ desire to satisfy patients’ expectations. Importantly, though, clinicians should not assume that patients and families necessarily want antibiotics. Patients simply want to get better,” said Chua. “In some cases, they may have a belief that antibiotics are the only way to get better, perhaps because they have been inappropriately prescribed antibiotics in the past for similar situations.” 

McCoy agrees that patient demand makes appropriate prescribing difficult and recalls times when patients doubt objective data. “Patients say, ‘I know when I have a bacterial infection that needs antibiotics’ and don’t believe that if the pharyngeal swab for Streptococcus species is negative that it rules out bacterial infection.” 

For the full article, please visit for the April 2019 issue of Pharmacy Today.