Inappropriate Antimicrobial Prescriptions Linked to Recurrent Clostridium difficile

Antimicrobial prescription before and after a diagnosis of Clostridium difficile (C. difficile) infection remained unchanged during a recent analysis.

Researchers from California reviewed the electronic health records of 210 Greater Los Angeles Veterans Administration patients between 2015 and 2016 in order to determine if a recent diagnosis with the infection affected the appropriateness of further antimicrobial prescribing. The investigators reviewed medication administration records for drug choice, duration, and dosage for all non-C. difficile infection antimicrobials prescribed within 90 days prior to and following a positive C. difficile diagnosis.

The study authors believed that a C. difficile diagnosis should “serve as a wakeup call to physicians that a patient has clearly suffered consequences of antimicrobial therapy and should thus prompt more prudent prescribing after it is diagnosed,” corresponding author Christopher Graber, MD, MPH told MD Magazine. However, this was not what the investigators discovered.

“We found that not only was there essentially no change in appropriateness of antimicrobial prescription pre- and post-C. difficile diagnosis, but that inappropriate prescribing after the C. difficile diagnosis was associated with increased risk of C. difficile recurrence.”

Three-quarters of the C. difficile patients included in the analysis were hospitalized at the time of their initial diagnosis and a majority was managed primarily by medical services. When the study authors looked at the risk factors, they learned that more than half of the patients were using proton-pump inhibitor therapy and hospitalized within the previous 90 days before their first C. difficile diagnosis.

In order to validate the appropriateness of each non-C. difficile infection antimicrobial course administered within 90 days pre- and post-infection diagnosis, the researchers deemed them inappropriate or appropriate based on professional society guidelines. There were 229 total courses of antimicrobials prescribed in the pre-diagnosis period, and of those, 93 were inappropriate. There were 102 courses given post-diagnosis, of which 44 were deemed inappropriate.

The study authors wrote that the most common reason for inappropriateness was that the antimicrobials were, in fact, not required at all. Other reasons these antimicrobials were deemed inappropriate were that they were the wrong choice or a continuation of an appropriate therapy longer than was indicated.

About a quarter of the C. difficile patients developed a recurrent infection within 135 days of their initial disease. The patients prescribed further courses of antimicrobials after their initial infection were more likely to develop a recurrent case, the researchers wrote, however, the study authors noted that patients who received inappropriate antimicrobials after their initial C. difficile infection were more likely to develop a recurrent case than those who received only appropriate antimicrobials.

The investigators further analyzed the source of the non-C. difficile antimicrobials given. The most common site for antimicrobial prescription was the hospital setting, where 17% were deemed inappropriate. Rates of inappropriate antimicrobial prescription were even higher in outpatient settings, nursing facilities, and the emergency department, the researchers said: 70%, 40%, and 26%, respectively.

Cephalosporins were the most common class of inappropriately prescribed antimicrobials, though tetracyclines, clindamycin, and antivirals also were represented in the study (but none were statistically significant).

“A recent diagnosis of C. difficile infection does not affect the appropriateness of subsequent non-C. difficile infection antimicrobial prescribing. Furthermore, inappropriate antimicrobial use after initial disease is associated with a higher risk of recurrent disease,” the study authors concluded.

The paper, titled “Lack of improvement in antimicrobial prescribing after a diagnosis of Clostridium difficile and impact on recurrence,” was published in the American Journal of Infection Control.