Broader-spectrum antibiotics over-prescribed in ambulatory settings

The majority of antibiotics prescribed for adults in ambulatory care settings are broad-spectrum agents, most commonly fluoroquinolones and macrolides.  These are frequently prescribed for conditions where no antibiotic therapy is needed at all, such as for bronchitis and colds, which are caused by viruses, according to a study published online July 25, 2013, in the Journal of Antimicrobial Chemotherapy.

“This study highlights the extensive use of broader-spectrum antibiotics in ambulatory clinical practice,” said Adam L. Hersh, MD, PhD, of Primary Children’s Medical Center, Pediatric Infectious Diseases, Salt Lake City.

“In many situations where they are prescribed, a narrower-spectrum alternative would have been more appropriate,” Hersh said. “Recent evidence indicates that when physicians receive feedback about their antibiotic selection patterns relative to their peers and to current national guidelines, significant improvements occur in antibiotic selection.”

In a retrospective, cross-sectional analysis, Hersh and colleagues used data for patients aged ≥18 years from the National Ambulatory and National Hospital Ambulatory Medical Care Surveys (2007–2009). These are nationally representative surveys of patient visits to offices, hospital outpatient departments, and emergency departments (EDs), collectively referred to as ambulatory visits. The researchers determined the types of antibiotics prescribed, including the use of broad-spectrum versus narrow-spectrum antibiotics, and examined prescribing patterns by diagnoses. Multivariable logistic regression to identify factors associated with broad-spectrum antibiotic prescribing were used.

In a previous study about pediatric care, Hersh and colleagues found that broad-spectrum antibiotics had become the majority of antibiotics prescribed in the United States and were often used inappropriately-“either because no therapy was needed as for a cold or other viral infection, or because an alternative antibiotic would have worked just as well, if not better,” he said.  “We wanted to see if the same trends were occurring among adults-and they are.”

Because antibiotic overuse is still very common, work still needs to continue to educate both physicians and patients that for many illnesses, antibiotics are not needed and have the potential to cause more harm than benefit, according to Hersh. 

“For good reason, there has been a lot of messaging about how antibiotic overuse causes resistance, and this needs continued emphasis,” he said. “In this discussion, we need to bring specific attention to the issue of the types of antibiotics that are prescribed-particularly the overuse of the broader-spectrum classes.  If we overuse these antibiotics when they are not needed, then they won’t work in the future when they really are needed because of resistance.  But we also need to make sure that everyone understand some of the other patient-level harms that antibiotics can cause, including serious allergic reactions, serious infections such as C difficile colitis as well as longer-term implications from disturbing the normal ‘microbiome.’” 

More studies are needed to better understand why physicians choose broader-spectrum antibiotics instead of narrower-spectrum ones, he concluded. “There are probably many reasons. There are opportunities to put evidence into practice around the use of benchmarking to physicians about what antibiotics they prescribe relative to peer physicians and to national guidelines.  Giving timely feedback to doctors seems to work-we need to do more of it.”